RE: XT 55/75 or 75/95??
7595. I would MUCH rather deal with an arrow that' s slightly stiff than one that' s underspined. An underspined arrow can drive you crazy.
Like was mentioned above, the Bowtechs will like a stiffer shaft because of the speed they are putting out. I personally think the shorter bows also demand a stiffer spine because of the increased string angle.
Good luck.