Go helical. Feathers. If you are currently using 3 inch, go 4 inch. If you are currently using 4 inch, go 5 inch. I will say, tho, the only problem with helical fletching is rest contact. If you are using a prong style rest, you will most likely have some contact on a hard helical. If this is the case, go to a drop away, or a whisker biscuit. Good luck. You will get it tho.