I saw an interview with Clarence Ashley where he refered to "sawmill" tuning. I forget the piece he played with it; but it wasn't Shady Grove.

I also saw a video of Buell Kazee demonstrating Mountain banjo styles. He claimed it was the custom to file down the frets as Dick described because the mountain folk liked to get notes between the frets. The banjo he used seemed to have the frets filed down from the nut to the fifth string tuner. He also says that it was the custom for Mountain banjo players to use tunings to minimize the fretting of any given piece.

Murray