10" stitched cotton wheels takes a hell of a big motor to turn. I use 8" on a 1.5hp motor and can easily stall it out. You don't need to sand to 2000 grit, I find 6~800 plenty when using dark grey or black compound. Use 'loose' cotton wheels and brown compo for primary finishing and an 'open' soft cotton wheel to get mirror finish (also lasts a lot longer between polishing's). Solvol or Mothers is actually too rough for a real good shine after mirror polishing and will dull surface leaving scratches, Use old well used cotton T-shirts, they are softer than re-cycled plastic
If you going to use an electric drill, use 3"~5" surface speed on smaller ones is always too low for a good finish mops.
Sand any real rough stuff with 80 grit first then work up to finer stuff. If you can remove covers (or have spares) use a larger wheel. I often use stitched Sisal with emery compound if I'm not doing any sanding.
Basically you try a higher grit depending on original surface finish, cast or pitted need very rough to cut it down, 'factory' finishes you can generally start with 240 after removing any lacquer or paint.
You can also make emery wheels if you get water based cutting compound, just soften the compound, add a little PVA glue then rotate wheels through 'mud' and allow to dry on the wheel. To reduce cut use ordinary red/brown compound.
The alloy polishing set at HF isn't very good but can be made to work.
Black emery compound from Home Depot is better than any of the other cheap sticks. If your going to do it properly you need to get stuff from Caswell but they are a little pricey sometimes. Oh, BTW, it's great to hear you finally got bike running properly 8)