Kinda depends on the airplane's attitude, I spend some flights in knife edge flight more then wings level while utilizing rudder to maintain altitude, climb, or dive and elevator to keep the axis of the fuse pointed straight to the path of flight. When I am flying knife edge loops, rudder is all about gaining or losing altitude.
Sure. But this is the beginners forum, and the OP was talking about how to make ordinary turns with a trainer, having gotten the impression from a ridiculous YouTube video that he was supposed to turn without banking much so as not to lose altitude. How we got from that to aerobatics, I don't know. When you're knife edged, the rudder functions much as the elevator normally does, and vice versa. But that information isn't really of much use to the OP, I suspect.