Well Steve,
It does seem as if you are going to take this up long term, so the first thing is to settle on some sort of motor. In my view, those Dremel and similar ones are a total waste of money, as they dont have enough speed control and are clumsy to hold and die quite quickly.

The low cost option is a micromotor from China, which ends up costing you about £100 when imported.http://www.amazon.co.uk/Jewelry-Micr...rds=micromotor

An alternative is a pendant motor, such as the Foredom. http://www.suttontools.co.uk/power-t...plete-kit.html

Once you have a motor, all the polishing you need for your items would be a set of radial brushes- no compound, no mess. But you would need to keep a set for each metal. http://www.cooksongold.com/category_...y=Radial+disks.

I have always avoided enameling for fear that once started it would consume my life. Dennis.