Tintin,
I was polishing a sprocket cover today, and took a quick before and after picture. I degreased the cover, then used black buffing compound on one of the pads that have a small adapter to use on a power drill. Then used the brown buffing compound, and I'm done. Power drill, buffing compound, and it took exactly 10 minutes, including removing and reinstalling the cover.
I've used the bench mounted ones before, but find they don't really save a ton of time, and it's more difficult to move the piece around, even with the guards cut off.
Chris in Boston