Target shooters that ive seen in local "shooting Leagues" us arrows that are like 2413 or 2512 something like that....

the spine on one of those is basically unbendable and they still shoot them well.
its my understanding that they use the fatter arrowsbecause it takes more space upon the target(cheat the lines on targets).

those bows are center shot with arrow rest and using a release,.....
from what i gathered , most of them pull around 60lbs but there arrows are spined for like 120#