I usually start figuring my hunting shaft by weighing the broadhead and insert I'm going to use. Then I like a longer arrow to reduce my gaps so to achieve that I had to jump up a spine from .500 to .400 in my hunting weight bows which are 47 and 50#. Buy the shafts and start with full length bareshaft tuning using a field tip and insert equal or near to equal to your broadhead combo. I like a very slightly weak shaft slightly nock high at 25-30 yards.

Have fun.