Don't know anything about building hammer dulcimers. But, as John said, lowering the bridge and nut on a mountain dulcimer is fairly simple. HOWEVER, it can mess up the intonation so the thing won't play in tune. My first dulcimer was an inexpensive plywood number with an action higher than everest. Lowering the nuts and reducing the string guages made it playable...but the tuning went to pieces. Fortunately I had saved the orginal nuts (made my new lower ones out of micara blanks from the music store) and was able to restore it to its original settings. It's not a great instrument, certainly nothing like my McSpadden, but it works as a loaner instrument for beginners who play with one finger or a noter.