I agree with Chad that helical does stabilize the arrow faster if needed. I also think it also has to do with how well your arrows are tuned to the bow and how good is your form release. If your release is real good and your spine is correct it may only take maybe a 3" straight fletch to get great flight. Also a carbon or aluminum arrows are going to be far more consistant spine wise than shooting woodies. So it all depends. Personally I shoot a 5" just offset fletch on my broadhead setups and 4" on my field point arrows.