I'm with PT. No tube peep.....no kisser button. My peep (at full draw) aligns perfectly with the housing of my Viper sight.....and that's how I know I'm aligned. I never have to "center" the pin within the peep. I just align the 2 rings (peep and sight housing).
In my bowhunting infancy, still.......I had NO IDEA that this was an option when setting up a bow. It came about as happenstance....when I was setting up my Allegiance. It's aided in my accuracy SO MUCH. In 2 3D shoots, last year....I never placed or scored that well. In my two 3D shoots since switching to this.....I've placed 2nd and 1st, respectively.