The really, really, tight trampoline was tried in the Tornado class, and it did not work. They even had trampolines cut so the threads was running diagonally to try and align the loads with the threads. Did not make much difference at that time. I dont see why it should be different on boats with curved beams?
I also dont like a loose trampoline, and that is why I tighten the lacings as much as I dare. Could you elaborate on your bungee lacing setup?