Nice job.. If you do decide to 2 tone them, you MUST paint the silver first! otherwise successful masking will be almost impossible...
masking RA's is actually very easy, with a roll of 3M fine line masking tape (3mm) as said paint silver first, leave over night, mask silver up to the sharp line in the casting, paint the other colour, remove masking, then lacquer the whole lot... doddle!
looking forward to seeing them finished, whatever you decide..
Here's a pic of mine I did some weeks back, polished rim, new BBS valves and center caps, and black bolt covers to finish (from dealer, 79p each)

Thom