Fagox to be clear, I was NOT disagreeing with your CG position. It was just interesting to me. By your video, your CG is wonderful...for you. The CG range on the Rebels is amazing and I agree with Dave and this discussion came up in my MAX thread. I suggested doing CG with landing fuel and caught a bunch of crap for it haha. But, to be fair, you have to look at the possibilities, not just the probabilities and there is a possibility that one could run the tanks dry which would be worst case and the most aft CG. Therefore, a check there is still a great idea. If one were to find the AC (aerodynamic center) of this aircraft, I think you find that our SM (static margin) is probably around 6-10% at the center of the tube which is why you can go 20mm in front or behind the back of the tube. The bounce in the nose is purely due to the position of the mains in relation to the CG and nothing to do with how it behaves in the air. I believe Andreas purposefully put the mains in that position to allow the aircraft to rotate effortlessly. You've done a great job with your Rebel.
Jan Roskam says place the mains 15 degrees aft of the CG. I'd say it's spot on.