I recently purchased a another bow and will be building some carbon arrows for it. I use Stu-Miller spine calculator. I can use a .400 spine or .340 spine, depends on how I build them. The .400 spine arrows come out at 8.7 GPP, FOC is 16.3, speed is 197 and arrow energy is 41.3. The .340 spine are 10.9 GPP, FOC is 17.3, speed is 177 and arrow energy is 41.2. My question is with the energy close to the same, which arrow would be the better hunting arrow or would it be a wash. I know heavier is usually quieter and better for the bow. Any help would be appreciated. Chris