Well the tubes I started low. I'd start higher if using power or try 3M. I did start at 220 but it doesn't take long to take down. Then a pass over with 650 and a wet 2000 (feathered it in). You can start 220 but be careful if using a drill. Especially if the drill (really the battery) is new and holds a charge well. If I had to do this over with only sandpaper, I would see what it looked like by hand. (Got a new dewalt that was screaming to be broken in). Key would be to check often. I actually prefer shallower engravings so I do like the engraving that's left. But it doesn't leave me many "touch up brushes" left. The touch ups will have to be by hand for sure.
The ring I spent quite a but of time with 220 to erase the knurlings (using the drill). Then as they almost faded I switched to 650 and finished with wet 2000. I did the same with a brass ring to use on my brass GGTS. But I do need some more fine work with wet 2000 by hand to blend it. The ring project was a gauntlet
thrown down by jojo a couple weeks ago when the JGGs came in. But before I have her that ring above, I had to photograph it. I'll do another ring soon.
Oops. The photo below shows the ring. The one above shows the JGG parts on GGTS. Both are the same TS.