All I can say is that last year I shot 4 3" feathers and was able to get excellent broadhead flight, even with big snuffers. The main advantages are easy nocking of the arrow, and better cable clearance due to the lower profile of the smaller fletch. Control for what ever reason seemed to be better than with 3 4" feathers and very close to what you would get with 3 5" feathers. I can't explain it all, but I know it works. This year I will probably end up shooting 4 blazer vanes on carbon arrows.