Mixed, compatible tunings.
General mountain dulcimer or music discussions
Skip,
I don't have a good grasp of modes; my ear is my guide. I only play noter/drone and, occasionally, get to jam with dulcimer friends who are chord/melody players and we blend fine.
I'm not sure I understand your last paragraph. (. . . can't you play a mixo tune in DAA [tuned DAdd] as long as you play the notes, not the fret numbers [TAB], and all of the notes are available? Am I forgetting the effect of the drones? )
I'll take a stab, though. As long as you have the notes available, I don't see why not. Give it a try and let your ear be your guide, bearing in mind the drone effect . Modern ears aren't used to the drone effect . 
Skip said:
Won't some of this depend on the style of the player, xxx/chord vs xxx/drone? Most of the folks I play with chord or fingerpick the melody, a few fingerdance. A couple of them can do harmonies, in DAdd.
I don't think many of them, maybe a couple, even know what a mode is. I know, technically, what they are, but don't really understand them. Probably because I play the separate notes as shown in SMN [or TAB].
I suppose the only way I can find out for sure, with my group, is to try it.
I'm probably wrong, but can't you play a mixo tune in DAA [tuned DAdd] as long as you play the notes, not the fret numbers [TAB], and all of the notes are available? Am I forgetting the effect of the drones?

, Strumelia! 
I didn't know there were still any Lee's Famous Recipe places left.
And he helps himself, too, to whatever he wants.
I love dogs!
I didn't know that you had a chromatic dulci, Robin.