Tuning for a 4 Equidistant String Dulcimer
General mountain dulcimer or music discussions
Hey @Dedicated-DAD, first you should know that there is a whole group here dedicated to 4 equidistant strings . YOu might consider joining, perusing the old conversations and perhaps starting a new one.
There are a number of ways people tune for 4 equidistant strings. Some just add another in the same pattern, so they might tune DADA. Janita Baker tunes something like D Bb A D. That gives her a chromatic scale, enabling her to play blues and ragtime and jazz. But she only fingerpicks, never strumming across all strings. I recently learned that Neal Hellman often tunes DAdd. Those two high D notes are not played together, but rather he plays in a drone style in that tuning and gets an extra high D drone that way.
I'm sure there are other variations, too. All of them equally "proper." Again, I urge you to joint the 4-Equidistant Strings group and pursue your interests there where you'll find more expertise.

I tune by ear and really struggle to get into DAG, and there is a bit of buzz, but it's so worth the try. This is my Teagan, a Wren by Feather Dulcimer, as well as my favorite!