I agree with John -- make a new nut & bridge and space the string as you choose.  Keep the old nut & bridge and put them back if you decide to sell.

You could make a new nut and bridge, carefully knock the other ones out, and cut the new notches any way you want.  This is assuming that you're handy with tools, measurements, etc.

 

I don't see how that modification would affect the historic value; you could always move the strings back to their original positions if needed.  Enjoy it....

So, I very recently found this 1973, Bob Mize, 4 string equidistant, Just intonation, nice friction pegs. Looks like possibly "Wormy Chestnut" top. Great sound to it, a real beauty. I am considering modifying it only as much as so it will be strung in the more common, 2 drone strings close together, and move the 3rd so it is fingered like a "modern dulcimer, but also could still be strung the traditional way.

 What do you think, I have some hesitation because of the "historic originality" factor. Believe it or not I found this on Etsy of all places. Never hurts to browse around!!

updated by @george-desjardins: 10/27/19 12:02:25PM