Not to pick on Washington Hunter, but he's the one who brought it up... I do not subscribe to the round pin guard theory. If you've got that good, reliable anchor, just pick the correct pin for the distance and let your eye automatically center that pin in the peep as you put it where you want your arrow to go. Really, your eye does it all by itself with no effort on your part, assuming you've got anything close to normal vision.
Your concentration should be totally on the target, not divided amongst the pin guard, however many pins are inside that pin guard and the target. All you should see at anchor is the target with a little colored ball right where you intend to aim.
Well I absolutely agree with Wash. I use a larger peep that aligns perfectly with my pin guard. I squint my left eye for just a slight moment upon reaching full draw.....kind of like centering a bubble on a level....to get the peep and the pin guard aligned.....and then it's eyes wide open (both). I never look back at either.....just the target and the pin (in that order of importance).
It's been the best thing for my accuracy. I used to center the pin.....but would never advise anyone to do that, now.