Hey guys/gals, Looking to get some new sights. I have a question that I can't really seem to find an answer for. What is with the different sight heights? For instance, why are the sights for G20,G21, etc, higher than they are on the G17, G22, etc? Basically what I'm looking for is something that will shoot poa/poi like my stock glock sights. That is, I want to use the dot to cover up the target and that is where the bullet will go. I am looking at Ameriglo Operators...but I've read a couple times that people have to swap the rear sight up for a taller one in order to accomplish this. But if I'm getting mine for a G21, I don't think a taller rear exists? Another problem is warren tactical sights. I really like these but they don't list what models they are for, etc. Do all warren sights fit all Glocks? I'm particularly interested in Ameriglo Operators though, but they are for my G21 and I want to cover up the target with front dot like I do with my stock glock sights. Whats the deal? Thanks everyone.