G-MAN,
I've always shot with both eyes open. I get to see more of what's going on, before, during and after the shot....whether I'm hunting or shooting 3-D.

The difficult habit to break, when you thinking about using 1 or 2 eyes, is not to drop your bow arm and look at the arrow while it's still in flight. Concentrate on the intended target and make sure your bow arm stays in place until the arrow has made contact. This type of "follow-through" will help your shot consistancy.

I use this method for both conventional and traditional bows.

Good hunting, Bowhunter57