What Brett said, plus, to answer your original question, a Skyray that's doing the pattern probably has +/- 30 or 45 degrees of deflection. With that skinny elevator on that fat stab you don't have to be shy about giving it room to travel.
And no, you do not ever need to increase the elevator area on a Skyray, at least unless you do something extreme like add flaps -- it's that skinny because the airplane doesn't have flaps, and as-designed it works just dandy. In fact, I have a couple of 40-sized trainers that I've built, with scaled up Skyray aerodynamics. They've both pretty much flown off the board.