Let me start off with my experanice this summer. Have been shooting 2314' s 5" feathers with a right helical. Bought some Gametracker cxhunter arrows with the vane and 2 degree offset...they shot the same out of my bow.
This quesiton gets brought up alot....and there was any artical in a magazine a while back. I would belive that a feather will stabilze the arrow better...and the helical will help a bit more. But straight seems to just fine for all practical porpuses and you may get more cleanerce on your rest.
thanks,