Traildad, thanks. 

@ Strumelia Thanks for the reply. You are right about the just intonation dulcimers. I can translate the notation you used to put in to the string calculator since it includes octave numbers. It is helpful to learn that I should lean towards the heavier side for tuning between C & D and G & A. Thanks for not giving up on me. Ken

@ Dusty Turtle Thanks for the reply. I don’t mean to make assumptions. I was using the notation that is used on the string calculator to differentiate between octaves. The notation you are using above works as well since it indicates octaves and I can convert it for the string gauge calculator. Thanks for your patience and help. Ken

Hi, Strumelia, I'm only passing on the information Mitchell reported about plain steel strings. Wound strings and plain strings of different metals would respond differently, I would assume. I don't imagine anyone would have a need to tune a wound string an octave higher than "normal."

Maybe someday when I feel rich I'll try his experiment with wound strings. But they're a lot more expensive than plain strings! 

I admit to having my doubts about that conclusion, John.  Are you saying one could tune a low wound D bass string up to the d note an octave higher without it breaking?  Not going to try that one myself.     Good experiment to try with a wound string you want to change out anyway though.

Not to muddy the waters, but to take one element off the table, at least temporarily: hammer and mountain dulcimer pioneer Howie Mitchell wrote about an experiment he made in one of his books. Beginning with a plain (unwound) light gauge steel string he tuned it up tighter and tighter, continuously checking the pitch, until it broke. He replaced it with a heavier string and did the same thing. The thicker string reached the same pitch as the lighter one before breaking. He tried a sill-heavier string and the same thing happened. It reached the same pitch as the other two and snapped. He kept going heavier and kept getting the same result. 

So string thickness makes no difference as to what pitch it can be tuned to. The gauge/tension affects tone, playability, and stress on the instrument, but not the highest note it will reach. As Strumelia points out, re-tuning fatigues the metal. Poor installation (like kinking the string while putting it on) and occasionally pinching or binding slots in the nut can also cause breakage. But the thickness of the string is not an issue.

Ok, now let's see what string gauges you might need on a 26" vsl dulcimer , for a 1-5-5 tuning for playing in the keys of A and G . (btw a 26" scale is very versatile length for various tunings, but we're sticking with 1-5-5 here)

TrailDad, we know you want a 1-5-5 tuning for the key of A, which would be Aee. On the piano chart I linked to in the last post, you'll see that those two high E notes are one step higher than the standard melody string (d) of the most common dulcimer tuning, DAd. On the piano chart, that high d is the very next key higher than middle C4, and it's shown as the 4th octave on the piano chart, D4. So, for your AEE tuning (or Aee if you want to be perfectly correct), those two strings would be tuned to E4. You always go LOWER for the bass string, so the A note lower than E4 is A3. Thus, your 1-5-5 tuning for key of A will be A3-E4-E4.

Let's see what the Strothers calculator suggests for those notes on a 26" scale.
It suggests a .014 string for the Bass/A string, and a .009 string for the two high e strings. 
However, you also know that you'll be wanting to retune all those strings DOWN ONE STEP to play in the key of G, 1-5-5, which is Gdd (G3-D4-D4). For GDD on a 26" dulcimer, the calculator recommends strings of .015, .010 and .010.

I would recommend the more robust set of .015, .010, and .010 for retuning between AEE and GDD in this situation. I've used .009 for high melody strings and have not liked them- I find them so thin they are both unpleasant to play on and they kink and break too easily. Using .010 gives a good feel and the strings will last longer. As to the .015 bass string for the tonic notes A or G, yes that seems pretty thin and indeed it may be a plain unwound steel string, but remember you are tuning to A3 not A2. You are tuning your bass string to the A3 note that is the SAME note as the middle string in the standard DAd tuning. So yes, it's going to need to be thinner than the average bass string.
Now if you wanted to experiment and use the A2 in the octave BELOW the usual D3 bass string in DAd, then you'd need quite a heavy bass string to avoid floppiness on a 26" dulcimer. The calculator calls for a .027 wound string for that A2 note (which they label as A'). That would make it so your two e strings were a 12th up from the tonic A rather than the usual 5th up. Could sound cool, but a bit less traditional. You might also need to widen your slots for a .027 wound string.
Incidentally here's where a "false nut" capo would enable you to put a more normal gauge bass string and work around this. Avoiding odd gauge strings is why people use various tunings and also capos.

So, on a 26" dulcimer vsl, using tunings of 1-5-5 only: 

Key of A:  A3-E4-E4
Key of G: G3-D4-D4
Both tunings could be achieved by using strings: .015, .010, and .010

I'd like to backtrack a bit and try a different approach. TrailDad, I do understand your question. You want to use two different sized just-tempered dulcimers to tune to the four common keys while sticking to only 1-5-5 tuning. I suspect the reason you want to stay with 1-5-5 is because that's the one tuning that your just-tempered instruments will sound 'sweet' in. Switch them to a 1-5-8 tuning for example will sound a bit sour, unless it's an equal tempered instrument. But rather than suggesting you explore a different temperament or vsl or different tuning or gauges, let's try to respond to your exact question and see where we get.  :)

Ok, so let's start with assuming you are going to use the standard string setup of having a lower tonic-tuned bass string (that's what 1-5-5 indicates, after all). For ease of understanding, let's also start with the most often used 1-5-5 tuning: DAA, for the key of D . 

Let's look at a visual chart of the numbered octaves on the piano, which will help us all stay on the same page:

piano octaves, numbered

There, we see that the heavy wound bass string tuned to D would be D3 on the chart.. the D below middle C. The A of the two other strings that are tuned just a 5th above that low D is A3 (still below middle C). So the typical 1-5-5 tuning for key of D is D3-A3-A3 on the piano.

========================

What gauge strings to use for that D3-A3-A3 tuning on a 30" vsl dulcimer?  The Strothers calculator tends very slightly towards light gauge recommendations, so if the note you want is between two, choose the heavier option. (Don't just automatically choose a heavier string than the Calculator says.) The Strothers calculator for that DAA tuning on a 30" scale suggests .018 for the bass string and .012 for the other two strings. Now, .018 normally seems pretty light for a wound bass string, but then 30" is a pretty long vsl, so let's continue for a moment...

Now, let's assume you will use the SAME dulcimer to play in C which is only one step down on all strings and is easy to retune to... from DAA to CGG. Looking at the piano chart, you know you will be going DOWN just one step on all strings from D3-A3-A3 to --> C3-G3-G3, and you don't want the strings to feel too floppy. That C3-G3-G3/key of C tuning on the Strothers suggests: a .020 for the bass/C string, and .013 for the other two G strings. Keeping in mind that the Calculator may run a little too light with its suggestions, in this instance between the key of D and the key of C suggestions, we'd choose the slightly heavier option- the key of C suggestions for gauges, to ensure no slack strings. They'd certainly not be so heavy as to break when tuning up one step from CGG to to DAA. 

So, for the 30" dulcimer, we'd choose the bass string to be a .020 wound string, and the other two strings to be .013 plain (unwound).  That should enable you to tune 1-5-5 on a 30"vsl dulcimer for the keys of both D and C .

I'll examine the same issue but for a slightly shorter dulcimer instead, for the keys of G and A, in my next post but I have some work to do on a job right now and will try to get to it within a few hours.  Hope that helps a little?

@Traildad, you are making a false assumption that a note using an upper case letter always refers to a note below middle C.  I tune my baritone dulcimer GDg. All of those notes are below middle C.  I use the lower case g to indicate that the string is an octave above the bass string. I also have an octave baritone dulcimer, meaning it is tuned an octave above that baritone, and I still indicate the tuning as GDg even though only the low G is below middle C and the D and high g are above it.  I also have octave dulcimers that I often tune DAd, but all those notes are above middle C.

In other words, the use of the upper and lower case letters shows how the notes relate to each other, not how they relate to some objective standard like a piano.

There are ways to indicate exactly which octave on the piano a given tone is from, but almost none of us bother with that.

Strumelia's blog was not specifically about string gauge, but she does mention that she stopped using a wound bass string and only used string gauges around .10 or .11.  The blog post is about how she gets to the main 4 keys of C, D, G, and A with two dulcimers, one that can tune to C and D and one that can tune to G and A.

If all you want to know is what octaves one uses for 1-5-5 tunings in those four keys . . .

C-G-G would usually be C3-G3-G3

D-A-A would usually be D3-A3-A3

G-D-D would be either G2-D3-D3 (as a baritone) or G3-D4-D4 (as a 3/4-size instrument like a Ginger)

A-E-E would be either A2-E3-E3 (as a baritone) or A3-E4-E4 (as a 3/4-size instrument)

Of all those notes, only the D4 and E4 are above middle C.

@Strumelia I went back and reviewed the blog posts

https://dulcimer-noter-drone.blogspot.com/2009/03/tunings-i-mostly-use.html

https://dulcimer-noter-drone.blogspot.com/2009/02/here-is-simple-diagram-i-made-up-to.html

and your response to Ron dated 2/24/2009.

Many times in both blog posts and your response to Ron you refer to the tunings DAA, CGC, CGG, EAE, DGD, CCG, AEE, GDD all to describe tuning in the keys of A,C,D and G. Nowhere do you mention a galax or the special tuning you now refer to with the .010 strings. I will admit that my question “ I’m trying to figure out which octaves all the notes are for each key.” could have included more detail. But the question is pretty straightforward and all the tunings are standard tunings and to my knowledge have nothing to do with the specialized galax tuning. I would hope it was clear that my question was about the different tunings you referred to in your blog. I still don’t understand why your answer was about string size instead of what octaves the notes are in. It is possible that the octaves are notated correctly and all strings are tuned below middle c. I am still trying to get what I thought was a simple question answered. I am sorry that I make you pull your hair out. 

I had mentioned in the 2nd post I was trying to figure this for 155 tunings so I wasn’t sure if you were saying that’s what yours was. I had tried to ask about 155 tunings in an earlier thread but I messed it up. When I’ve got both dulcimers with the proper strings gauges in front of me I’ll explore that subject. I figure it will be easier when I can actually tune the dulcimers rather than just talk about it. 

Since we are talking also about avoiding breaking strings...
One other point I'd like to make is that although I might be able to use just one dulcimer to retune into four different keys, especially if it's a middling scale length and using correct string gauge to do that...  even though I 'could' tune to all four keys with the same strings without breaking them, the mere strain of tuning up and down frequently between tunings for the keys of G and D (a whole three and a half steps between G and D) can be enough to very much shorten the normal life of a string.

I remember walking around oldtime music festivals with one dulcimer, joining in on one jam session after another, and retuning back and forth between the keys of G, A, C, and D every hour or two depending on what folks were playing. A whole day and evening of doing this often was too much for my strings and one or even two of them would snap at some point. Not because I was tuning the string too high (because i had no problems while at home where I changed tunings much less often), but because I was going back and forth 3.5 steps too many times and creating metal fatigue.
People who play dulcimer in jam sessions with players of other instruments need to be able to change key fairly often. So this is another reason for a noter player to use two dulcimers in jamming situations.. at least it was for me. Chord players who use capos or fingering notes on various strings can avoid some of these issues- they are able to utilize more ways to play in different keys without so much retuning.

Again, for active festival or gathering jamming scenes where I want to play only dulcimer, i use one dulcimer for the keys of G and A, and the other dulcimer for the keys of C and D. Other folks have cool ways of avoiding snapping strings by using 'reverse' tunings or capos and under-string capos (sometimes called false nuts). 
Robin's mentioned EAA tuning is an example of such a reverse tuning for playing in the key of A, in mixolydian mode. It's a 5-1-1 tuning, and can be great for playing in mixolydian mode rather than ionian. Her tuning neatly avoids breaking strings because she can simply tune DAA and put a false nut capo under the bass string at fret 1 and then play in A. (her middle string then becomes the tonic drone, and the bass string capoed becomes the "5th", and the melody string is tuned to the tonic note).
There are lots of cool ways to be able to play in various keys- using string gauges, capos and false nuts, reverse tunings, tuning to a different mode, using extra frets, or using more than one instrument and/or different VSL lengths. Understanding all of these different methods is a process that usually involves years of playing and endless 'lightbulb moments'.   I'm certainly still in that process myself. (may we never stop learning!)

Believe me it's an awful sinking feeling when you are having great fun playing at a campsite jam at 1am and suddenly a string snaps and you have to trudge off somewhere far away to find a place with enough light to be able to change a string because the night is still young! Not easy to change a string at night by flashlight, not having three hands.  ;)  BTW other times I sometimes opted to bring one dulcimer for the keys of C and D jamming, and a banjo for the keys of A and G. The banjo is always heavier to haul around at a festival, though.

@traildad No, EAA is not 1-5-5.  DAA is 1-5-5.

I'm not the best person to explain this because I am, really, a by-ear player.  Here goes, though.  DAA is 1-5-5 and I will try to demonstrate how this is.  To visualize it, hold your hand in front of you, palm side up.  Consider your thumb as representing D then think of your index finger as E, your middle finger as F-sharp, your ring finger as G, and your little finger as A.  The D you started with (your thumb) is 1.  Counting across your fingers in the order stated above, you arrive at your little finger, A, which is 5.

I see where the confusion is coming from. TrailDad, you've been quoting from this 2009 blog post I wrote in my noter drone blog:

https://dulcimer-noter-drone.blogspot.com/2009/03/tunings-i-mostly-use.html

If everyone reads the entire blog post I wrote, and also the various comments between TrailDad and myself at the end of that blog post, it will be clear that some of this confusion (again) is coming from the fact that I typically use all .010 gauge strings on my oldtime session dulcimers, and thus the AEE and the GDD tunings I am describing there are all in the high octave (like with my Galax dulcimer)- with no heavy bass string and no middle gauge middle string. If one reads my entire noter blog post linked above (plus the Comments at the end of it from a month ago, where TrailDad asks these very questions and I answered them), most of the confusion in this thread could be avoided.

Personally, I would not recommend a 30" scale dulcimer in order to use these tunings, even with all .010 strings. It could well work just fine, but it's pretty long IMHO and the strings might be real tight. A different approach might be called for at 30". In my blog post I describe my 28.5" and my 26.5" dulcimers I use for these tunings. The tunings TrailDad has laid out in his previous post are the tunings from my blog post but they are tunings I use with all .010 strings tuned in the higher octave , on the two VSLs I've given. (btw if i had a 30" dulcimer I would probably just lower whatever tuning i was using by one whole step to the next lower key, if I was just playing alone at home).

In my blog I've written extensively about having ditched my bass string for oldtime fiddle session playing and gone with all high octave light gauge strings, but when my specifics are taken out of their blog context, people naturally assume the tunings I wrote about are to be used with the usual heavy wound bass string and a medium thick middle string most dulcimers use. Then they start using the string gauge calculator based on that assumption... and up come various dilemmas concerning the tunings and the vsl and and the gauges. This is a good example of why it's problematic to quote 'articles' (i.e. blog posts) out of context without identifying where the information is coming from. It's also one of the problems with blogs- because they are a continuous string of related posts, and in many blogs each post builds upon what has come before it.

If one goes back to read my blog post from 2009 , there are no tuning challenges such as those we are trying to solve here. The confusion comes simply by trying to apply my "all high octave gauge strings" tunings to dulcimers with typical low/middle/high gauge string setups. It's like trying to pound a square peg into a round hole. Hence the subsequent talk of baritone dulcimers (tuned a whole octave down from what I described in my blog) by folks trying to be helpful, to solve this 'tuning dilemma'.

My advice is that if one is going to use the typical string setup of a heavy wound bass string, a middle gauge middle string, and a thin gauge melody string(s)... and i think it's a great standard system... then don't try to apply the same tunings i suggested for using with all .010 strings- it won't work well. Probably better to use tunings and/or gauges that are more normally used for the keys of A and G. It's better to figure out WHY you want or need to play in particular key or tuning rather than assuming you need to play in it.  My advice: pick a few tunes, figure out what key you want to play them in, then figure out the tuning method you want to use to tune for those tunes. Trying to understand and anticipate all situations before one encounters them is a difficult and frustrating path.

All this said, several good players have now mentioned that having only two dulcimers in slightly different vsl length can enable you to playing in the four most common keys pretty easily without lots of retuning (and without constantly changing strings). Others can do it with just one dulcimer, especially if they use either a 'reverse' tuning, OR a capo or under-string "false nut" capo to raise the bass string without breaking it, like Robin Thompson does- watch her videos for tips on that- and she's a very creative and expressive player.  :)  Hope this helps.

p.s. TrailDad thank you for pointing out that typo in my blog post- I went back and corrected it- you were right about that!

Would this be considered a 155 tuning?

What exact pitch to tune the strings to for each of the four (C,D,A,G) 155 tunings is a whole other subject. I missed the mark when I asked that question before. The topic thread went awry and I dropped out. I figure I can try again when I have dulcimers in front of me with the correct string gauges so I can learn hands on rather than theory so to speak. 

@Ken-Hulme I left the name out on purpose to avoid it being about the person instead of the question. It is a well respected member. I assume personal experience can vary and something like a bad batch of strings might lead us to different conclusions. The benefit of the forum is getting input from the larger community to hear what others experience. All things being equal I’d rather have two matched instruments so it’s easier going from one to the other. Thanks for your input. 

"So I’ve read the recommendation to get one dulcimer in the 30” range and one in the 26” range to help this issue."

Not sure who recommended this, but IMHO it's not a useful recommendation -- Either VSL can easily give you ALL of the tunings you want with more than adequate ease of play -- simply by selecting the right strings.

"I’m pretty sure it’s not impossible to use 2 30” VSL dulcimers instead."

True -- or two 26" VSL instruments.


"I guess I’m trying to figure out how much playability I’ll lose going with two 30” dulcimers."

IMHO -- not enough to even bother thinking about 


"Is the benefit of having one shorter VSL worth making an extra effort to find one or is it splitting hairs?"

IMHO -- "Splitting hairs" is putting it mildly.   'Not worth even thinking about' is closer to reality.  IMHO there is NO benefit to having a shorter and a longer VSL instrument. 

After you've been playing for a couple years you will decide which VSL you prefer, and gravitate towards instruments of that size.  Decades ago I built and played 28" and 30" dulcimers... over time I have come to prefer short scales... these days I build and play 24"-27" VSL  dulcemores.

The Strothers String Gauge Calculator suggests strings of .023 for A and .016 for E on a dulcimer with a 30 inch VSL and .026 and .018 for G and D.  You might try .024 and .017 and feel comfortable tuning to both.  You will be tuning to the G and A below the standard D tuning.

For what it's worth (and it might not be worth much), I tune to the key of A by beginning in a "home base" tuning of DAA then placing a small piece of wood under the bass string at fret 1 to raise the bass string to E-- using EAA to play in the key of A.  I have standard dulcimers of varying VSL's and tune to any tuning I wish within the limits of what the string will take.    

Ok it makes sense a baritone would need to be designed to sound best in the lower ranges. I want to stick with a “standard” size dulcimer. I reread the article and the shorter VSL is to help prevent breaking the EE strings when tuning in the key of A. I’d like to just follow the advice if I can get a dulcimer that fits my needs in that length. If not, how well will a 30” VSL handle tuning to the key of A with the correct string gauges?

Below is a quote from the article.

 “I chose my shorter scale length dulcimer (26 1/2") for tuning to the keys of A and G, since a high EE was the highest note of all that I'd be tuning to in the four keys I'd be playing, so the shorter length kept less stress on the strings tuned up that high. And I chose my longer scaled dulcimer (28 1/2") for tuning to the keys of C and D, since GG was the lowest note of all that I'd be tuning to in the four keys, and a longer scale would help avoid those low G's from feeling too floppy.”

A baritone dulcimer is built to be tuned about a 5th lower than a standard dulcimer, AEE or GDD. The difference is not so much about VSL (27" baritones are common) as string gauge, action and building a body that resonates well at the lower pitch.

An alternative is to go a fifth higher than standard. McSpadden's Ginger model is an example of a dulcimer built to tune AEE or GDD an octave above baritone. These models often have a shorter VSL (23"-25") and a smaller body. They are convenient for travel and the higher pitch is a contrast you can hear when playing with standard dulcimers or guitars. For me the Ginger/alto range has the "high silvery" sound of a traditional dulcimer, while a baritone has more of a guitar sound. Just my opinion of course.

The shock of moving from a 30" VSL to a 23" inch VSL might be overwhelming. Or it might be fun, depending how much you enjoy a challenge! 

It's entirely up to you whether you'd prefer to go up or down in pitch from the standard DAA/CGG tuning. Within reason, any dulcimer of any size could be set up for the tuning you want. Certainly a 30" VSL could be set up as a baritone.Talk to your favorite builders and ask what they recommend.

I know someone who plays noter/drone on a Ginger (without the 6.5 fret) and is well pleased, but he does use an overhand grip on the noter. I have my eye on the Ed Thomas replicas, thinking their relatively small, shallow bodies might sing beautifully in the alto range, but that is merely speculation (and dulcimer acquisition disease).

@Dusty Turtle Yes that is why I want two dulcimers. I haven’t considered a baritone dulcimer. I heard of them but I don’t know what is different about them from a standard dulcimer. 

@Traildad, you are looking for a standard dulcimer (tuned D or C) and a baritone dulcimer (tuned G or A).  This is not a complicated proposition and there is no trouble changing tunings in the 1 or 2 note range that you discuss as long as you have the right string gauge. I have dulcimers in those two tonal ranges and switch between those keys all the time.  Not a problem.

I am not sure what you mean by a "specialty noter drone dulcimer" unless you mean one with partial frets that only sit underneath the melody string.  

You have the 1-5-5 tunings correct.  If you are tuned to A,  a 1-5-5 tuning is A-E-E.  In G, it would be G-D-D.  I am sure you can find the right string gauge to be able to go back and forth between those two keys.  

In D, a 1-5-5 tuning is D-A-A and in C it is C-G-G.  Again, you can find the right string gauges that will allow you to switch back and forth.  That will not be a problem.

However, you will not be able to move between A-E-E and D-A-A on the same set of strings.  I assume you understand this and that is why you want two dulcimers in two tonal ranges.

Sorry if I’m not explaining this clearly or using the right terminology. I have one dulcimer with a VSL of 30”. I was planning to pair it with one around 26”. Because I am looking for a speciality noter drone dulcimer I can’t order one from just any maker. That limits my choices. I can get a second 30” VSL if I want. I’m trying to decide if I can get by with two longer dulcimers instead of one longer and one shorter. The plan is to use one dulcimer to switch between the keys of C and D and the other for the keys of G and A, standard 155 tuning. Of course using the correct string gauge on each dulcimer. I would like to have good playability with the looser stings and also avoid breaking the tightest strings. So I’ve read the recommendation to get one dulcimer in the 30” range and one in the 26” range to help this issue. I’m pretty sure it’s not impossible to use 2 30” VSL dulcimers instead. I’ve discovered there are several very good dulcimer makers out there that don’t know diddly squat about noter drone dulcimers. I guess I’m trying to figure out how much playability I’ll lose going with two 30” dulcimers. Is the benefit of having one shorter VSL worth making an extra effort to find one or is it splitting hairs? 

What are the notes for 155 tuning? I’m sure I’ve got some of these wrong but I think the melody E string for the Key of A is the tightest string and the Drone C string for the key of C is the loosest. The goal is to get good tension on the loose strings while not breaking the tight strings by using a heavier gauge on one dulcimer and a lighter gauge on the other dulcimer. I understand the wisdom of the advice to change dulcimers when going from a low key to a high key. Having two dulcimers will solve a large part of the problem of playing in high and low keys. I just don’t know how much better it will be to also get the shorter VSL. 

Key of A is AEE?

Key of G is GDD?

Key of C is CGG?

Key of D is DAA?

Thanks for the help. 

We need to know three things to help --

1.  the VSL of the dulcimer(s) involved,

2.  the current string gauges on each instrument,

3.  the tunings you are trying to reach on each instrument   

You said " I think a melody string E is the highest note."  which makes no sense. Any string can be any open note.  It all depends on the gauge of the string.   

A string particular gauge of string cannot necessarily be any note -- notes too high for a particular gauge will break a string as you try to tune up.

I should have mentioned that I am trying to figure this for 155 tunings. I think a melody string E is the highest note. Two dulcimers for four tunings. Depending of course on the songs I favor at the moment it could be frequent changes up or down the one note. I can’t remember which VSL was recommended for the high tuning. I should re read the blog.  Maybe it was the lower notes that were better on the shorter VSL. I do plan on using the calculator to get the right gauge strings. If I can’t get the shorter VSL I’m hoping that using two different dulcimers with the right gauge of strings will still allow good tension for the low drones and no breakage on the high melody strings. Thanks. 

If you have the right gauge string to start with, you should be able to go up or down a note with no problem.  On my standard dulcimer I often tune down to C and occasionally up to E, so all three strings are moving between two whole steps.

For a high D string and a 30" VSL, the Strothers String Gauge calculator suggests a .009, and for the C below that, a .010.  That gauge errs on the light side, so a .010 should easily work for either.  For the A, it recommends a .012 and for the G a .013.  Again, you could use either, but I would go with the .013.

I’ve read that a shorter or longer VSL is beneficial for different tunings especially to keep from breaking strings on the highest notes. I'm wondering how problematic tuning between C and D or G and A will be on a 30” VSL if I can’t find a shorter VSL dulcimer I like.