Here is a bit of a radical idea for your 3rd old dulcimer Cindi. How about stringing it up with 4 melody strings (4 x 0.010) and tuning them all to 'd' so you have a dulcimer in d,d,dd like a Galax dulcimer is tuned. It may sound crazy but for sessions you won't miss the bass strings as the other instruments (like guitar) will over power your bass string anyway. In d,d,dd your dulcimer will 'froth' along at the top of mix providing a very audible rhythm. If you listen to some of the tunes played by Phyllis Gaskins with her string band you'll hear how this tuning works when played with others.
The tuning d,d,dd means that you can play in the key of D with a noter or by fingerdancing starting the scale at the nut or play in the key of G starting at the 3rd fret (over d,d drones) - without retuning. If you put a capo on the first fret you can play in the key of A, both major and minor depending on your use or not of the 6+, starting the scale at the 4th fret and playing over e,e drones.
When I go to sessions (quite regularly!) I always carry a Galax tuned dulcimer, and it is the tuning I use the most as the sound carries really well because your dulcimer is sitting in a unique part of the sound spectrum. You need a quick right hand to whip up a rhythm - my preference is to use a quill and whip it across the strings.
It is just an idea - but if you do have an old dulcimer doing nothing at present then it could be fun to set it up in Galax tuning and have a go with noter and quill.