RE: Helical or straight vanes??
I've always liked feathers. Lighter and more forgiving... and they stabilize the arrow better. I've always used a right 5-8 deg offset w/ a straight clamp. Straight fletching was very popular w/ the TM hunter style rests due to fletching contact. But a offset will be more accurate. You want some spin in the arrow. It's pretty hard to get a full helical on a small carbon arrow... and too much helical causes excessive drag.