I agree on the cork screw. I love the looks of them but they are a pain to get to stay on the shaft to dry. plus they seem to come loose quicker.
the last couple I've made I cut the full length uncut feather strip in half, making them about 5" long and straight fletched with 6 of them on it.
I played around with them one year. I make a couple of corkscrews, a couple of 4 fletch, couple of 3 fletch and a couple of 6 fletch. then I got out in an open field and just started shooting. the corkscrews acted like they had parachutes on them. wasnt much noticable difference between the 4 and 3 fletch. the 3 fletch would fly twice as far as the 6 fletch.