I'm working on some instructional clips but they wont be done until fall that really break down a lot of the stuff that other instructionals are going to gloss over.
Probably the best thing you could do is post up a video of a few of your attempts, and we could pick them apart (if you can handle it
It depends on the kite if you use a true progressive edge, because your edge loading profile will cause the kite to do different things, right ? I dont think you will stall a properly powered kite with a progressive edge (because you have to know when to release it
One thing I noticed when I started to unhook was that the difference in body position between my riding ready to unhook pos, and the point when I had unhooked and the weight was in my arms but my chicken loop was still close to the hook, was that it was a super awkward position!! And you are almost instantly having your arms pulled away into a more arms out in front of you position, instead of with your hands down low. The timing of this with your edge caused the kite to do some weird translations in the window (just slightly) but enough to ruin speed & consistency between pop.
I now ride with a bar with short throw but a long distance between the chicken loop and bar, so when I unhook, I'm only coming ~2 inches out of position instead of 6-12 " out of position. I dont know if that makes sense.....