In all my years of shooting CZs, I have never seen this question addressed
by CZ: What is the appropriate sight picture for a compact CZ or for any CZ? I tend to use #2, and that's what works for me for most of my different handguns, which aren't all CZs.
Those who are into long-distance shooting and Bullseye enthusiasts tend to use #1. (Bullseye shooters know the exact distance to the target and have their sights set for that distance, so holding on specific spot is the same as holding on the bull.)
I find #3 troublesome if you're trying to do any kind of (precise) shot placement on paper targets that are under 20 yards -- as too much of the target is obscured by the sights. For up-close-and-personal (self defense shooting) #3 is fine and arguably best.
Glocks recommends image 2 below (or did at one time) in their manual, while FN recommends sight the "Combat Hold". Most folks call image #3 the "combat hold" but there are others that call #2 the "Combat Hold." If you're using 2 and should be using 3, you'll shoot low. If you're using #1 and should be using #2 or #3, you'll be shooting way low or be off the target!
