First and foremost the spine and FOC must be good, if you cut the arrow shorter than 27" unless you use a 125 gr BH. The FOC will not be good and I think probably for 50# not below 320gr. But you just have to look at speed, penetration, and trajectory and select a happy medium so to speak. Also you got to consider the weight on the nock end of the arrow for the FOC for example feathers VS. Vanes would be a big difference. Wraps also take away from FOC.