Nice work.

If you want to easily get the stainless steel on your games back to close to factory finish for little cost AND effort, buy one or two of these.
https://www.rshughes.com/p/3M-Scotch-Brite-CB-ZS-Coated-Aluminum-Oxide-Flap-Wheel-X-Weight-1-3-4-In-Face-Width-3-In-Diameter-80799/051144_80799/?gclid=Cj0KCQjwpreJBhDvARIsAF1_BU29pTNs71xXL_VJnpSJUt6dk0xN727ihPF5VSFWfTcjHXkTgq5XNowaAmWKEALw_wcB

I would expect one of these to get you through all 3 games. It won't polish them but will provide very close to the grain finish they came with from the factory.

The biggest issue is being able to run the wheel straight down the rail. If you can chuck your drill in a fixed position and guide the rail through the flapper wheel you will be amazed by the results.

I do the top of the side rails and the lockdown bar on every game that comes through and they look new. The one thing they don't overcome is deep scratches.