I haven't had anyone brave enough to let me shoot over their chronograph at 50 yards and test the difference in retained speed between vanes and feathers downrange.
Arthur,
You are more than welcome to shoot my chronograph...uhh, I mean...shoot through my chronograph...uhh, I mean shoot over my chronograph whenever you want....
As for vanes overtaking feathers...I just do not have the courage to shoot through a chrono at 50 or 60 yards since I do not practice regularly at those distances but wouldn't you think that the specific design of a feather fletch, multiple bristles, would cause more drag than a smooth surface like a plastic vane?