I am by no means a mathematician OR a rocket scientist...but I aspire to play one on TV.  That being said, It takes time for momentum to build, and most YouTube info is geared towards compound bows >65# and distances >30 yards.
Your choice is a heavy arrow with less FOC, or same spine low GPI and higher FOC.  What'll it be???

For example: 40-45# bow, 500sp, 465gr with 19% foc  vs:  500sp, 435gr, 22%

A third option is "moo" point.

Quote from: BAbassangler on November 29, 2025, 01:30:46 PMI am by no means a mathematician OR a rocket scientist...but I aspire to play one on TV.  That being said, It takes time for momentum to build.

Like a rocket, an arrow reaches its maximum momentum when it reaches its maximum velocity.  Unlike a rocket, an arrow does not have any internal fuel, so reaches its maximum velocity as soon as it leaves the string.

Excuse my ignorance, but what is "moo" point?

The one that flies the best 

Quote from: durp on November 29, 2025, 03:40:20 PMThe one that flies the best 

Right on!  Personally I just start with the arrow I want to shoot and try and build up from there.  11-12 grains per pound as the goal. Example my long bow I shoot a .204 ID arrow that has 6.7 gpi. 80 grain inserts and 150 grain BH gets to 460 +/- grain total. Never bothered figuring foc.  I was looking for lighter faster and these fly like lasers. 

Joey Tribiani from 'Friends', wasn't the brightest guy and didn't know moot.  Thanks for the rocketry crash course.  I've been leaning towards "moo", or faster is better, as the ft-lbs, in the 3Rivers calculator are near identical, might as well get the speed as long as quiet enough.

Right on, right on, Flemish Twister and Durp.  I've jumped up 1 and 2 spines and they never fly as good when they're the same length, and always end up around 700gr.  They hit like a freight train, and I get to shoot bigger heads, but they just don't seem to ever bareshaft as well.

Because of my age, I'm relegated to hunting with 40-45# bows, so I have some familiarity with bows in that range.  Both of your examples are close to 10 gpp, which is my preferred arrow weight for hunting.  I prefer your option that uses a lighter shaft and a heavier point weight to get there, as I understand from reading Dr Ashby and others that that configuration is generally more lethal than having the weight more evenly distributed along the arrow.  However, your example are close enough that I'll go with "moo" point.