another newbie question

Ideally you run the rough grit until all cracks and pits are gone. This would be tough with most woods. Run a burnish cycle overnight immediately after polish. I use powdered Tide laundry detergent. Many use 20 Mule Team Borax. Use more water than normal as it is a wash cycle. This will clean the drum also. Have you had the tumbler long enough to be polishing already?

I use diamond compound where there are imperfections. It doesn't leave the polish streaks. Try washing with a soft brush. The longer it dries the harder to remove.