I don't think you can be given an RAS if you are VFR (that may be "No controller will give you one"). He will expect to vector you around the sky to avoid other traffic, and that's not the time to say "sorry, I can't go into cloud".
I've flown under RAS, and it's hard work. You'll cover a lot of sky. RIS is a lot better unless the airspace is busy, in which case...