Gymnast, tumblers, cheerleaders, come here!?

Hey, im a tumbler(: I'm trying to learn my full twist. I can pretty much do it (round off backhandspring full) with very little spot. I CANNOT do a standing on the trampoline. If this makes sense to you: when I twist very little in the air, I end up doing a half. And if I twist as hard as I can, I do a half. I cannot twist all the way around. Tips?