I make sure that they are all the same. Helical will cause the arrow to spin faster. I don't believe quick spins need any. Helical also slows the arrow but causes it to stabilizes quicker. Helical also can cause rest problems. How important is it, I don't know. In bow tuning, bare shafts and fletched shafts are to hit the same spot, you decide. I leave my fletchings 3/4- 1" above the nock grove with a little right helical.