That's true. You have to master the pattern first. That is always the same- right rudder, down elevator, left rudder, up elevator for left rolls. Backwards for right rolls. The only thing that varies is the timing of the imputs and the amount of imput. If you can't sit and repeat that pattern with your transmitter, your not ready. Hovering or torque rolls require quick, reactive, random imputs that can't be practiced without a sim or an airplane in the air. You can practice the pattern for rolling harriers anywhere, anytime. Then it is just a matter of timing that pattern to your plane.