By now you know that on FOTMD there are lots of opinions on any given topic ...
For me, the day I picked up a 23" VSL McSpadden "Ginger" was a total game changer. It was January, 2011, and I found it for sale in the vendor area at Kentucky Music Winter Weekend. Maureen Sellers was selling it and there was a box placed next to it for the buyer's check. I wasn't feeling very well, having gone through 2 grueling operations in the previous 2 months and was sitting out one of my classes that Saturday afternoon. I had never seen a dulcimer this size, much less held one, and I was instantly enthralled with it. Everything that I had struggled to do on larger instruments (with longer VSL's) now came easily with the Ginger. My confidence grew as my fingers easily found the notes for song after song. I played almost non-stop for 2 1/2 hours, wrote out my check, dropped it in the box and took my new Ginger to my final class of the day.
The Ginger remained my favorite instrument for several years. It was set up to be tuned DAd, so I used it in both my private playing and in classes and jams. Eventually, other instruments caught my interest and as my collection grew I had a variety of sizes and VSL's to choose from. I found that I was now comfortable with VSL's up to, but not exceeding, 28 inches....but I still prefer a VSL around 25-26 inches.
This has been my experience. As always in the dulcimer world, see what works for you!
Best wishes in your journey!
Mc Spadden Ginger , 23" VSL
McSpadden, Schnaufer model with 29" VSL
Jan Potts, Lexington, KY
"Use what talents you possess; the woods would be very silent if no birds sang there except those that sang best." Henry Van Dyke