I shot 27" long250's out of my 70# Allegiance. I did tune them and had zero problems and great groups. The Binary's are more forgiving to softer spines than other cam systems. If youare shooting a Single cam go with a stiffer arrow. If youreally want a lighter arrow check out the Carbon Tech Cheetahs. They are a top notch light weight arrow shaft.
Good Luck!!

Dan