foug,

I shoot about the same length and all and have found that a .500 spine is Ok up to about 63# with 75gr tips. You put heavier tips on them and you'll really be pushing the envelope. You would certainly be better served, I think, with a .400 spine. They'll be a little stiff on the lower end of the weight range, but would give you much more latitude if you want or need to crank the weight up around 65# or more.