I have a short barreled Evo3(141mm) so to get it to reasonable fps it's gotta m120 spring and a excellent air seal. Should I be using a harder bucking due to the higher power of my system or is a 50 degree bucking fine ?
If the current bucking is hopping whatever weight bb you are using, properly then it's fine.
You'll be seeing similar fps at the hop as everyone else, the weight of the bb will matter more and you should have plenty of adjustability to offset the increased spin on the bb.