The resin/fabric scales shape fairly well, but tend to clog up belts. I did the rough shaping with a 50 grit belt on the 4x36" belt sander. Making each side close to the same thickness is the trick.
Careful with the heat from a cotton wheel spinning at 3500 RPM. It can melt the polyester and it's back to sanding again.
After the buff, it's starting to look like a polished stone.