Yep, I agree. One or the other having both just adds more weight to your string. I know a few that use both, my best friend does. I just can't get him to take it off

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You could go one better and use a No Peep and take them both off

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And remember if you use a kisser button you have to use it properly. It can't just touch the corner of your mouth. Your mouth moves and is not a consitant anchor. It needs to touch a tooth or something solid.
I prefer to touch the string to my nose, let the string touch the corner of my mouth (where a kisser would be I guess) and be aware of where the arrow contacts my face. For me it is between my my bottom lip and my chin.
Paul