Any of the ball-ends, regardless of their marketing, should do fine -- at least that's what my experience suggests. I purchase individual guitar strings for all my dulcimers -- any decent music store that sells guitars will have lots of 'em on hand. You can also order 'em: http://www.juststrings.com/singlestrings.html
For instance, for my dulcimer in GDD tuning, I do .22 for the bass string and .12 for the other strings. On DAD dulcimers, I do .24, .18, and .12. Those are both Folkcrafts, by the way, so probably the same neck length as yours.
For instance, for my dulcimer in GDD tuning, I do .22 for the bass string and .12 for the other strings. On DAD dulcimers, I do .24, .18, and .12. Those are both Folkcrafts, by the way, so probably the same neck length as yours.