as some have mentioned or alluded to, use a carbon shaft, scout out the stiffness and grain/inch mass weights of each, wight out the nock and feathers, then figure out how much to load up the front end.
i use beman ics 500's, 29.5" raw length, bohning nock and 4" four fletch, 100 grain brass insert = 335 grains.
with 250 grains of point and steel adapter i've got a 585 grain arrow w/27% foc. adding in a 155 grain internal shaft footing nets me a 740 grain arrow w/32% foc.
swapping the 100 grain brass insert for a 65 grain alum insert, plus the internal footing, gives me a nice 665 grain arrow w/30% foc and 12gpp for my 55# longbow.
lots can be tweaked by selecting the right weights of insert, adapter and point.