Do you remember in the 50's and later when you could buy blank shafts of port orford cedar and make your own, incl making the fletching 'machine' w/ the bent wire to shape the feathers (many of which were plastic later) and serve your own bowstrings after making them from a spool of Dacron(?)
Then they also had 'battleshafts' which were like 'forged' cedar as they were smaller in diameter and stiffer and of a darker brown color? Those arrows were somewhat akin to a 'ballistic coefficient' of a bullet, i.e. similar to the difference between a 'long thinner' 7mm bullet, vs a 'shorter fatter' .308. bullet. Same principle in effect. IIRC the battleshafts were compressed somehow under heat, like an autoclave process?)
60 yrs ago I used to pick grapes for a farmer just to get $16.20 for a dozen Easton aluminum but don't remember if they had different levels of 'spine,' 'spline.'
Nearly all circu****ential shapes/objects have a 'spine.' Pool cues, golf shafts, etc. Physicists have argued for years whether 'spining' unless grossly present, has any real effect on the end results of using such shapes. You can find the hard spine of a golf shaft by using 2 roller bearing races or simply laying the shaft in a bath tub with a few inches of water and watch it rotate then stop. All have a 'hard' spine and a 'soft' spine. Orienting the 'spine' in different quadrants ahs an effect on shaft flex, but none of it has ever been proven to make the golfer a better golfer! (Some even have 2 spines but that is just another source of arguing and creates even more discussion among 'engineeers' who can't play golf except with a calculator))
To many back home, shooting the 'compound' bow was a 'prosthetic' device tantamount to 'cheating!'