I don't use stones, probably should have some but most of my work is better stippled. I do a lot of pierced celtic work, mostly cast, so have a lot of small mold lines and flashing to clean. I have adapted several of my needle files to fit into quick change holders, and to be a usable length. With the adjustable speed etc, they do a good job. Bet you could do the same thing with small stones!.
I do think the elephant looks great!