Before you get too concerned with getting perfect cascade rotations, can you do a decent-looking half-axel on its own yet? Sorry if I underestimate your ability here
However, if you can't, or maybe even if you can already, perhaps try this:
1. Fly side-to-side of the window, doing half-axels at the edge where the kite is stalled and they are easy. Practice this until you can get them looking nice and flat.
2. Gradually do them closer and closer together towards the middle of the window (you will have to give more slack for the same effect), until...
3. There is no flying in between each beautiful, flat half-axel, et voila, you have your Randy G-looking cascade!?
PS. For the best half-axels, I find it helps to give a very small `pop' with the bottom hand first, immediately (no hesitation at all) before the main input with the top hand, followed immediately by lots of slack from both hands. This first input pulls the lower wing of the kite slightly towards you, just like with a regular axel where if you want to pop with the right hand, for example, you pull the left wing of the kite slightly forward first.
I don't know whether this applies to cascades really - perhaps the kite is already in ideal position after the last rotation, or perhaps it's not so important. Can anyone comment on this?