Well whatever his question was, probably at least one person has answered it by now haha

Well it is all speculation until the original poster replies and tells us what he means by "blue notes."

Ken

"The dulcimer sings a sweet song."

Since he's a guitar builder and probably player, I think he is referring to blues notes.That's the reason for my recommendation.

Is he referring to BLUES notes -- which frankly can be any note at all.  Or BLUE notes which would only refer to some chart/table of notes which includes some colored blue?  

Dwain please correct me if I'm mistaken, but I think you may have increased all those notes by an octave(or two with A5 and decreased by 1 with F3 relative to the other notes) though I am not aware of GFG being a normal tuning, perhaps you meant GDG, (one full step down from AEA or a 1-5-8 in G major?) with normal tunings being d4d4A3D3 A3A3A3D3, G3G3D3G2 which are normally notated as D-A-dd (mixolydian tuning) or D-A-AA (Ionian tuning) GDGG (baritone mixo)
Also I think you meant to say that a diatonic scale is like a piano without the black keys, not a piano without the white keys.

updated by @nate: 04/13/23 02:47:08AM

Ah! I just looked up the term "fret scale chart" and see that it is a chart showing the pitch generated at each fret position for each string. That is easy to do with an instrument with a standard string tuning schema, such as the guitar's EADGBE.

The dulcimer is an entirely different instrument in several ways:

• Players use all sorts of tunings. D5D5A5D4 and A5A5A5D4 are to very popular ones. G4G4F3G3 is another.
• Dulcimers are essentially diatonic, like a piano without white keys
• Dulcimers have different scale lengths, ranging from 24" to 28". That allows for even greater range of tunings, and various sets of strings will be found best for each dulcimer
• Dulcimer players ask for different chromatic frets (I presume that is what you're referring to as 'blue' frets). Popular 'extra' frets are the 1-1/2 6-1/2, the 8-1/2, and 13-1/2. This is a notation developed to describe the chromatic frets on a diatonic fretboard.

So the fret scale chart for a string tuned to D5 would be DFGABCD (the fret pattern of an Appalachian dulcimer is in Mixolydian mode, meaning that the 'black' keys fall between the 2nd-3rd frets,

I believe he is referring to the 1.5 and 4.5 frets, the 1.5 I think is the minor pentatonic blue note in D, both allow for the melody string to play a d minor scale, the .5 fret also helps with minor scale chords

updated by @nate: 04/12/23 11:37:06PM

Your best option may be to make it chromatic. The frets are basically located using the same procedures as you use making a guitar. If you decide to use the dulcimers diatonic fret placement, you will need to 'bend' notes to get the blue notes. You may want to study the MD fret board before making a final decision although the extra frets can be installed later. Or build two, one diatonic, one chromatic.

What, exactly do you mean by "blue notes".  With dulcimer there are the basic diatonic frets, diatonic frets plus one or two extras, or full chromatic frets like a guitar.  In 40 + years of messing about with dulcimers I've never heard the terem "blue notes",  

Are you asking for a list of fret measurements for chromatic frets? The stew mac calculator can be set to 'electric guitar' and will then show placement for all 12 frets in an octave.
Are you asking for a chart which shows scale degrees and how to fret them? I am not aware of one for chromatic, but this chart has the diatonic frets and you could add onto this yourself.
https://everythingdulcimer.com/tab/chord_chart_dad_major.pdf
For every fret that is not included on this chart, you can identify it's note, then identify the notes of the other frets you are playing and with a chart like this 
https://www.michael-thomas.com/music/class/chords_notesinchords.htm
you can determine what chords you are making with these frets. So whichever frets you have, I promise it's a pretty quick process to transcribe your fretboard into a chart of scale degrees in various keys or letter notes.

I have a fret calculator spreadsheet, if you use MS Excel. Stew-Mac has one too, but doesn't allow you to specify extra frets. Mine shows all extra frets.

I can't attach a spreadsheet file here, but send me a private note with an email addy and I'll send the spredsheet. MS Excel 2016 or later needed.

can someone help me with a fret scale chart of a mountain Dulcimer.
Preferably with the blue notes