As others have mentioned, you will most likely need some offset to your fletching. Most factory fletched arrows have some offset, but it is not easy to see. Fixed heads catch the air and tend to steer your arrows off course. I just completed broadhead tuning on my hunting bow, and found no real difference between offset fletching and helical, at least out to 40 yards. Some of the newer low-profile broadheads (Slick Trick, Rocky Mt. Turbo, NAP Nitron and Crossfire, Wasp Boss and Boss Bullet) out today will require less control by the fletch to shoot well, however.