I've tried sizes 4 and 3 in the woods. They both allow enough light at dusk and dawn. The 3 is smaller which of course made for tighter groups. I plan on trying out the #2 peep next fall. Ken at nitehawk recommended against a #3 for hunting but it was as good if not better for letting in light than the industry standard 1/4" round peep I had to begin with. I'd recommend a #3 then go from there. That way you have 2 directions in which to go.