You will have to experiment and I don't know what the J-bar has done to the angle. But in your video one could see the the angle was much too severe and was trying to raise the rail instead of pushing the door closed. The lower the rail is in the rear the straighter and smoother the push will be.
That makes perfect sense to me. I'll play with it tonite and see what happens when I lower the rear a couple notches on the supports.