I used the 1200 degree aluminum-colored paint on my rotors. It is possible to get to most of the interior vanes if you spray the edge. On the fronts, I painted the friction surfaces, and have had no ill effects. On the rears, I tried masking, and I'm not happy with the results. There's just no way to get it perfect.
1200 degree paint is probably overkill.
I don't recommend silver. No matter what you do, the boundary between the friction surface and the painted surface will not be perfect, and a little bit of rust will be there. Also, the silver paint really shows brake dust and other imperfections. Black will hide them.