Everyone seems very eager to promote a big jump or concentrate on jumping but I feel the other way about jumping techniques. The smaller your jump, the faster the technique is and the far less obvious it is. The point of the jump very often is not for the added height but for added speed.
Sometimes you can jump without actually jumping... er confused? Let me explain, when you jump you foot leaves the floor meaning no friction meaning much faster spinning. However, if you lift your foot up so its only barely touching the ground, as in no pressure applied to the ground, then the same effect is in place.
My instructor often encouarged us with the jumping reverse hook kick and especially the reverse heel kick to do this. If you jump high you have to bend your legs more, which is very obvious to your opponent and the whole thing is slower.
The aero step is a pretty difficult technique and not really that much more effective in my view for the hook kick. A 360 backkick using the aero step is the only really fancy technique that can do the job of a good score in my experience.
When I learnt the kick you are having trouble with, I initially started just by going onto the ball of my foot, then taking more and more pressure off the ball of my foot with a suitable push up until it was just aerial. I think having it 'just' aerial is probably the best for the speed.
I must add however, that in certain jumping kicks the jump is done for the height alone. For example, the jumping sidekick off the spot is really done to get your hips to head height to you can take the guys head off... not that great for competition!
Just my thoughts
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