Agreed, forget doing oil on RC paper. It won't soak in and will just rub off and look poor since it sits on the surface. Even glossy FB is not ideal, in my experience. The ideal medium is matte finish fiberbase paper. Also as mentioned oil pencils are great for small areas. A white plastic-type works great for removing overpainted areas. Something like this:

http://www.staples.com/Staedtler-Mar...product_274795