For fixed blade b/h, you really need offset, or better yet, helical. I flech my own and was using a GKF 3D Rover rest with the prongs, I never had a clearance issue with 4" vanes. It was not as severe as some traditional arrows and feathers I have seen, but it was plenty to spin, and thus stabilize, the arrow with a b/h attached. I used to shoot Muzzy 3 blades, now shoot Magnus Stingers, both heads fly great out of a tuned bow. You will need the spin that helical or offset gives you for good b/h accuracy.
Now for target archery, whole different ballgame. Small straight fletches, even as small as 1.5" and you are good to go. Lighter means faster, which means more forgiveness for yardage misjudgements.
I prefer a little heavier for hunting, and I shoot 3D with the exact same setup as I hunt with. Kind of like off-season, you play how you practice. By the time elk season comes, I am very comfortable with distances and performance of my equipment.
Play around, fletch your own, see what works best for you. That is one of the greatest things about archery, endless tinkering.