You might have better luck with the stopper/powerline-adjuster/Prussic-knot device, getting a better grip on the powerline, if you use a much larger diameter powerline, which will have a "coarser weave". Also, for the prussic knot cord, itself, try using some old bridle line rope, which has a more "abrasive" grip on the power line.
Even with these modifications, you will probably find that you can not easily depower the system, when there is a lot of tension on the front lines. You will probably need to do the same thing that kiters do that use the "below the bar" cleat system... they have to bear off and decrease the tension on the front lines, and make the needed depower adjustment, at the same time .
I am glad to see that you are still working on the details. Keep us posted.
Hello, thanx for the advice for the prussic knot line i will check what i have laying around.
I have considered using a thicker CL-line but that would also create much more friction on the swivel by the CL. So, I dont know if that is the answer, hmmmm.
The stopper does not work at all. One possible solution is the use a longer plastic pipe so there is a bigger distance between the left an right cl-line where the run through the stopper. This would make it more z-shape and hance wedge better the bar is against the stopper.