IMAC rules state that the nose must drop before rotation starts. Some planes will do this on their own while others like straight wing Edges hang on forever.

Two seperate things here to discus. First is getting the plane slowed down in a reasonable amount of time. The easiest way to do this is do a BIG Immelman before the spin. Make it large and your speed will naturally be lower and you can reduce throttle before you level out and perform the half roll.

My main Imac plane is pretty Draggy so it slows down nice, and I don't throttle back until I roll upright, but as soon as I do, the throttle is chopped and then feed in more up elevator to hold the line straight and then pull more to get the stall to break where wanted. The box is zoneless so positioning wise, it does not have to be in the center. When the nose falls rudder comes in and the spin begins.

Practice this a few times and you will get it. If your plane does not break, just falls over, then you will have to learn how to "make it appear to break", ie. feed in quick down elevator before the rudder and back full elevator.

Practice practice

chip