If your kick is coming out low, you may need more flatspin. That means maybe you’re taking off forward too much. Remember if you take off with your left foot then you should jump to your left (and not forwards).
Just as with the B-Twist Round you don’t need to be perfectly horizontal for this trick. In fact it’s a lot easier if you are just a bit more vertical, because that will make it feel a lot more like a Cheat 720. If you want to be more horizontal, then you really need that flatspin to make room for the pumping motion.
Hypertwist can be a good prerequisite but in my opinion it’s more useful if you want to learn B-Twist Swipeknife. For me personally Hypertwist and Hyperhook feel completely different.