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.
To modify or not to modify
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