I have the unusual problem of over rotating my tantrums. I don't do one of those low, fast tantrums but i just seem to over rotate and land on my back. Should I be cutting in less? Also i am pretty extended so I dont think i am curling up in a ball and rotating fast.
Hard to say without seeing a video... Sounds like you may not be transferring as much of your momentum into height as you are into rotation. I would really concentrate on going UP not out on your tantrums and see if this helps.
Steve is most likely correct. I would say go up, tuck your legs in, rotate over, then when you spot your landing, start to extend your legs and/or let the handle out to slow down your rotation as needed.. let me know if this helps
Aerial awareness. It sounds like you are getting lost in the air. Do you feel yourself over-rotating? Do you know where you are in mid-air? Practicing back flips on a trampoline can help you build more aerial awareness.