Ive never given it any thought. I always spin test my arrows, two or three blade. If they spin well, and are attached to a arrow that is tuned to my bow, it will shoot just fine. There was a time I liked to line all my two blades up to where they were vertical when nocked to my bow. But ive found it makes no difference if the arrow is tuned properly.

I have a brother that use to insist on lining his two blades up with his cock feather.