I'm sure it's been asked a hundred times....

How much would helical feathers slow down an otherwise identical arrow with straight offset feathers?

I'm asking because I'm about to buy my first fletching jig (Bitz), and need to decide which clamp to buy.
I will mainly be hunting with the arrows I make, releasing with fingers off of a flipper rest.
Even if I shoot target, I prefer to use my hunting setup to stay with the same form and feel.

I like the concept of the added stability that a helical fletch would give to my arrows bearing fixed blade broadheads, but I don't want to reduce my speed too much since I only pull about 55 pounds for a speed of about 210fps. I can shoot with a more arched trajectory, but don't want to if I don't have to.