Most important: Training. The tool doesn't know what it's doing- only you do.
Get a Foredom tool with the foot controller and the 1/4" drill chuck.
We had a variety of tools to do what you're describing. We might start with an abrasive roll, them go through the grits up to rouge for a final polish. Shiny is nice, but it's much more important for the shape to be correct and safe.
PIA? Colt revolvers like the Official Poilce, etc. I much preferred Smith and Wessons and Rugers. The Security Six and GP-100's are how revolvers should have been made all along, IMHO.
Autopistols: Things like Hi Standards or Colt Woodsman. I'd take a dozen Ruger Mk-II's first. Oh, also Smith and Wesson 39/59 series are pretty "part-rich" compared to a 1911.
Other tools: *Fitted* screwdriver tips, and a bunch that can be cut to fit. Starret 1/16" punches- you'll break them, but it's a frequently used tool.
A parts washer with Simple Green in it (don't let it soak). An air compressor so you can blow solvent out of parts- if you don't have to take that trigger group apart you won't have to spend any quality time on your knees under your bench looking for that spring that hit escape velocity and disappeared
(hint- use your magnetic tip screwdriver and listen for the "tink" to let you know you found it).
A sharp scribe- not a dental pick. A scribe that's about 1/8" shank with a 90-degree tip on it. You can shove the pointed straight end through things like trigger groups, line up all the parts with the pointed tip, push the pin in from the back and you're done.