If you have a consistent anchor point, the big peep shouldn't hurt much. It's more of a check guide to make sure you're doing everything else right. Some shooters don't use peeps at all and shoot just fine. I use a peep, mine is a middle sized peep, as far as peeps go. I match my peep up to the sight I'm using. I like my peep to just touch around the edge of my sight housing when I'm getting ready to shoot. If I'm not mistaken, I believe that's the standard recommendation. As booner said, the smaller peep will cut out light, so thats a big downer for those low light situations. However, a smaller peep does help you line up straighter than a bigger peep. There's a peep called a Superball. It's a peep that has a housing that is tied into the string on your bow, then you can use a little wrench to switch the aperature to give yourself a variety of hole sizes. I think it's something more common for targeting shooting, but it's something to check out. I'm sure there's other peep sights that do the same thing, I just happened to know specifically about the superball. I'm thinking about getting one. Then for practice I can use the smaller peep to help work on my form, and for hunting I can switch out to a larger peep to help gain some light.