1. First, a warning. Once I got a library book written by an MD about repetition stress injuries. He specifically mentioned using a guitar pick as a cause of damage to the hand. I think it's fine to use a pick, but don't use it all the time, and don't use it for hours.

2. When I play fretted dulcimer, I use a thumbpick on my right hand. I use different picks for different styles. Some sound classical, some sound like bluegrass.

Why confine yourself to one sound?