I've used old fly rods.
I'd bought old fly rods when ever I could find them cheap at yard sells flea markets. After about 10 years I had 17 rods and a lot of old reels. But I started collecting them about the same time. NO IT WAS THE SAME TIME. I now have 28 reels.
I used only the butt end section, start with 14 butts. I kept a couple sets.The butts all seamed to be about the same (spine). I rasp them round made 6 with trade points I made 6 with knapped heads I knapped 2 with judios. But spined them to a 55# bow I was building for someone at the time.
I shot all the arrows as I spined them to the bow. They all shot like they leaped off the shelf.
If it dos'nt look like your arrows are leaping off the bow.
Your not getting all out of your arrows you can.