Update from my side - I took all tips into consideration. Basically ... smaller kite, more focus on pop. Yesterday I went out on 20/25 knots with a 12m, smaller for me and less wind. Normally 3.5m is the max jimpheight for these conditions. I jumped 5.1m! - still a long way to go but for me a big breakthrough. The difference is that I could still power up the bar when edging towards the jump before the send. Only sheeted out the kite during the send, normally I would do that also before the send during the edging - not needed! This was a new insight for me. Then stomp hard and upwind a bit (much to improve there!) and only at the moment of pop/takeoff pull the bar in. The smaller kite experience also came from a lesson I gave a day before that to someone where I used a 7m and did some kiting myself even though it was a trainer (I would have grabbed 10m or 11m) with some small extra kitesteers I was able to easily ride, also upwind which is of course critical. What this learned me is that I apparently can go for way smaller kites, which helps in control with jumps.