Thanks fellas....
Jeff - I use a 1/4 sheet palm sander to do most of the sanding work. I hold the ash pan just over the edge of the work bench and rotate it as I 'sand' it. Doesn't take much pressure and the pan is pretty rigid. The ash ring is harder to hold the way, so I just hold it in my hands. Left hand inside the ring & right hand on the sander. Zero pressure applied to get it out of round.
The sander leaves swirl marks, but once you work through 400 grit sandpaper it's quite smooth. Still has (smooth) swirl marks, but that's where the 0000 steel wool comes in. Going in one direction, it only takes a few minutes with the steel wool to erase all the sander swirl marks and get this puppy shining.