I would appreciate some advice. When you change or replace the rear sight, how do you set the windage? Does getting the rear sight into dead center as aligned with the front sight usually work? Using the grooves that run the length of the slide on my P99, I can do that well enough (9 grooves, dead center at 5). If I do that, then how do I test at the range whether I've got it right? At what distance? Keep in mind I'm not a very good marksman. And finally, in theory, is the windage screw, as its name implies, to correct for cross winds? Or can the correct adjustment sometimes appear to eye to be off center but be right because it's correcting for some lack of "straightness" of the barrel?