thanks all, for the referrals

hi Bob, i can help you with the correlation between spine and mass, more so with our own shafts- but the formula kinda stays the same for all the woods- just the size of the numbers vary.
i am more than happy to help you with any question or technical data i can help you with, and i certainly dont expect you to purchase shafts from us.
If you are planning to build them by hand with a "shooting board", there are lots of folk on here that do that heaps.
if you are going to build a jig- either a router based or table saw based jig- i can help some with that- i have built a few of them, but more so if you are planning on using the veritas jig- thats how we started many years ago- and i notched up a lot of hours on that jig

thats just if you need some assistance. i am sure you are more than capable