That is a good suggestion Matt. That would be the only way to know for sure, of course both the top, bottom, and sides would have to be out of the same piece of wood, on both dulcimers. Have you already done sibling dulcimers; one with tung oil and one with another type of finish? Is that how you know oil finishes dampen the sound?
I have been using tung oil exclusively and am not aware of any sound 'dampening'. There are some posts on the web that allude to a slight dampening effect, but i cannot find any serious research addressing the dampening concern. If anyone knows of such a study please let me know. Maybe my ear is not sufficiently 'tuned' to notice any 'damping'.
Personally I would not use linseed oil:
When used as a wood finish , linseed oil dries slowly and shrinks little upon hardening. Linseed oil does not cover the surface as varnish does, but soaks into the (visible and microscopic) pores, leaving a shiny but not glossy surface that shows off the grain of the wood. A linseed oil finish is easily scratched, and easily repaired. Only wax finishes are less protective. Liquid water penetrates a linseed oil finish in mere minutes, and water vapour bypasses it almost completely. [5] Garden furniture treated with linseed oil may develop mildew . Oiled wood may be yellowish and is likely to darken with age. Because it fills the pores, linseed oil partially protects wood from denting by compression.
Very interesting article.... thank you!!!
Selah, you are getting good advice and the members here are very knowledgable and have help me tremendously. From a personal perspective, I don't really care for the 'twang' or ''buzzing'/'squeal' you get when using a wound string. It is a matter of personal preference.
Thanks Ken, easy way for the novice builder to work with sound hole design.
Ken, can you share you thoughts regarding number of sq. " per surface area of the top of the instrument? For example hourglass shape will have different surface area than a teardrop....possibly...
There are pliers specifically designed to remove frets, some builders may use a very thin knife, working it across the length of the fret on both sides, some frets may be tapped on the very end in an upward manner (not usually recommended). Any method requires protecting the surface of the fretboard as much as possible. There are even thin metal 'fret shields' that may be used during the process. If the fret has been glued in it is going to be even more difficult. Just go slow and easy.
I am sure other members may have suggestions.
The name of my last build is VERY descriptive! I experimented with a couple stains and it failed; hence named: The Ugly One. 
Despite appearance, it sounds fairly good. 
I have just been in touch with Don's wife, via email. I was hoping to discuss his building a true replica of a TMB a few years ago. She replied "He isn't building anymore due to health problems."
The bridge and nut may be set up....just be sure he installs 4 tuners so you have that flexibility.
Folks, I am one of the newest members here and this forum has already been invaluable in helping me learn about both building and playing a dulcimer. Let's ALL chip in so Strumelia doesn't have to support this website out her own pocket; it's valuable to all members in so many ways.
Great story. 
hmmm people go asleep when I play also.....
Well, we've, my family, has had a lot of fun with the old 'bug the bus driver and chaparones song' called 99 bottles of beer on the wall; and I really enjoy playing 'Nobody Knows the Trouble I See' but retitled it, 'Nobody Knows the Trouble I'm In'. On a more serious note, I really like playing 'May the Circle Be Unbroken', and 'Blowing In the Wind'.
You may like the lack of 'squeeking' as you slide up and down the fretboard. I, and my family, do.
I'm in the non-wound camp also, the 'whine' for lack of a better term, is very distracting to me.
I have tried a thumb pick, but prefer the tactile sensitivity of my thumb on the strings. A callus has built up and somewhat protects the skin....not a preference of all but it works best for me. :)
"No Body Knows the Trouble I've Seen", but I have retitled it to: "No Body Knows the Trouble I'm In".
Also, some players/listeners really don't appreciate the 'squeal, buzz, twang' or whatever some call it on the heaver strings and those (.022" - .024") strings are available in plain steel or a 'silent' wound string.
Thank you for all the responses. Based on what has been said so far, I am going to build for 4 strings (double melody) option, but will be stringing for 3; unless otherwise requested.
This question was asked a couple years ago without any responses. I, being a new builder/player, would like to pose the same question. I have looked and have found very little discussion on this topic and look forward to hearing from those with more experience. Bottom line it may be simply a matter of 'personal preference' but I would like to hear others opinions: Single or double melody strings? 
http://fotmd.com/strumelia/group_discuss/1294/personal-preference-question-on-stringing
Be careful, if it drys too fast it will be prone to checking and cracking.
Nice looking pieces of wood! I would dry them 'as is' and then work them down to dimensions using whatever tools/machines you have available. Here is a slab of burl maple I air dried for 3+ years in a barn and then worked it down for making the dulcimer I have posted in another thread: 
It was a good time and Ken and Sally are very gracious. We did have fun on the topic of 'dulcimers' and Ken is no slouch when it comes to building and playing them; and he has a great singing voice! :)
It's in the 60's here now and the plumbing freeze problem happened a day or two after we left when it was 3 and 4 degrees overnight. Luckily the split, in the copper pipe in our guest cabin, is accessible and it appears not a lot of damage done.
One would need to see the wood to determine; weight along won't do it. 2 lbs is not an unusual weight.
When??? I guess for me when after building my first dulcimer, a few weeks ago, I found myself prepping wood for 3 more. 
I can't help you with more info regarding your particular instrument, but I do nave more info on John Maxwell; plus an original 45 recording of him and his people playing. If you wish I will be glad to copy and send you the info. Is there a notch in the nut/bridge for a 4th string?
My Maxwell, see pic. in signature on left, was built in 1976. Maxwell, from Cookeville, Tn. around 2300 dulcimers between the mid-60's and late 70s. My instrument has 4 strings (equal distant), and does not have the 6 1/2 fret. My guess yours would be mid-60's to early 70's, but can't be sure.
I want to keep control of my pick without gripping it too tight, and not worry about it slipping in my fingers. I tried the sticky 'monkey stuff' and other substances but just wasn't pleased. The solution is a pick that doesn't slip, I have total control without having to grip it tightly and don't have any 'greasy stuff' to wipe off my fingers. Using hollow punches, 220 grit abrasive paper and a 'tiny' drop of super glue, I made two discs for each pick and applied one to each side.
Works beautifully!!! You can see I am still experimenting with various pick styles. 
Here is my alternative to a possum board, I call them 'skunk boards': They are made them from misc. lumber in my shop. They each have 4 stick-on non=skid plastic feet on the bottom and 2 feet on the tops. The top two feet on each are the only contact with the dulcimer. These skunk boards provide minimum dampening of the sound; they are small and easy to transport and fit under any style of dulcimer. They are not visible when placed under the dulcimer. :) 
Here is my alternative to a possum board, I call them 'skunk boards': They are made them from misc. lumber in my shop. They each have 4 stick-on non=skid plastic feet on the bottom and 2 feet on the tops. The top two feet on each are the only contact with the dulcimer. These skunk boards provide minimum dampening of the sound; they are small and easy to transport and fit under any style of dulcimer. They are not visible when placed under the dulcimer. :)
I will be tickled if I can learn to play well enough grandkids and other family to want to listen and join in singing some of the 'oldies' songs I learned around campfires in my pre-teen and early teen years. On Top of Old Smokey, Kum Ba Yah, America, This Land is Your Land, When The Saints, etc. etc. Right now it appears it is going to take a lot more practice. 
It would seem to me the closer fit your case is to the length of your instrument the less space for it to shift and bang around when being transported? 
