It really just sounds like you're not getting enough total-body rotation before you leave the snow. Once you launch, the rotation you have is all you've got. You can screw around with rotating upper and lower body in different directions, but you can't really increase your rate of spin overall. You have to get your rotation going on launch. As snowolf says, have upper body pre-wound in the opposite direction, then just before you launch you whip your upper body around in the direction you want to go. Since the board is still on the snow providing a foundation, your lower body won't counter-rotate; instead you'll give yourself a net rotation. Once you launch, you'll just continue to rotate.
Yeah, that's me, Tracer Bullet. I've got eight slugs in me. One's lead,
the rest bourbon. The drink packs a wallop, and I pack a revolver. I'm
a private eye.