Thanks for the input. I don't know how serious a competitor I will be (though I would like to think I'm the next big thing and at this point it will be my every day carry gun (the Glock 19) that is called into service.
tom
I have Warren FO/Sevigny rear sights on the G19, that said, I think you will be fine with XS. From what I understand you'll just have to be aware of a different sight alignment at longer distances. Then it will come naturally after some practice and use.