I shot 3" parabolic out of an A handle Bear (1 of a matched pr,both w/custom limbs) for about 10 years or so. If the setup/tune is spot on,they're great... and I still shoot this bow... but,it isn't very forgiving on those,"bad days". Which,isn't a problem really.... I'd just grab the same arrows with 4" shield cut(burned) and carry on. The other A handle is about 5#'s heavier and with just the slightest bit of tune difference,really prefers 4".... with 4 1/2" being for offdays.
Edit to add; these are all 3 fletch