Less twist < less drag = faster flight . If your bow is tuned properly, arrows match bow weight and your form is good , you won't really have to depend on heavy helical fletching to fix that arrow flight. Some broadheads will give you more trouble in tuning than the others , but lotsa folks use reg. 2 deg. straight fletch on 3" vanes without a hiccup... It is trial and error kinda deal.. You just have to find a proper balance for yourself....