I've shot 4 fletch, mostly 4" feathers, though I've used 3" & 5", for about 20 years. I like it because you don't have to think about which way the arrow is loaded on the string - however the nock fits on, will work - no worries about the cock feather being in or out.
If you don't get too carried away with oversized fletching and too much helical, you won't notice any more speed loss at distance - in fact, because they are lower profile, 4 - 4" fletchs may have less wind resistence than 3 - 5".
I use a Bitzenburger jig, which I think is 75x105.
According to some of Ashby's studies, when you get into extreme FOC, you actually need less fletching.