I've always shot 3, with a solid helical. I dont know the degee anymore... it's as much as my fletching jig will allow without the fletching adhering poorly. I found that sweet spot years ago, and have not adjusted it in... maybe 15-20 years... ooph!
At this point I stick to 3 (blazers) because they work well for me and I have a bunch as a result of buying 100 vane packs. That said, I see a number of guys going to 4 fletch so it's had me curious at times. At this pint though, my rest wouldnt work with 4 fletch, so until a new bow happens I wont even consider it.
My gut though, Dan, says that it should stabilize better given more surface area thus more drag on the rear of the arrow. But at the ranges most hunt at, is that needed? No clue!
If you make your own, fletch a couple 4 fletch arrows and do some comparisons to see - accuracy? Have a friend "super slow mo" video you shooting from just over your shoulder (from behind) and watch flight in the videos... If it's better for you, it's better.
One thing I definitely like, is that you add material back there increasing visibility of your arrow. Less of an issue with a lighted nock, but still a positive.
Wired to Hunt just had a great podcast, maybe you've heard it already, with Andy May. He goes into great detail with his arrow preparation. One of the things he mentioned was testing his arrow out of his bow before fletching. In his case the arrow naturally wanted to rotate to the left without fletching, so instead of forcing the fletching to correct the arrows natural tendency he switched his helical direction and noticed tighter groups. I certainly haven't gone to that length, but it might be something worth checking out.
