You really don't need a rear sight in a hd or shootout. It's just a matter of getingyour front sight on the target, many guys only use q front night site. I have on all my glocks for 20 years. if you want a target gun, then it's a different story, since most glocks are set up for 25 yards the standard rear sight will do the same job as the night sight as far a accuracy, they are all the same "front sight" height and width.
A 17 l or a 34 or 35 are target guns, the rest like 19 and 26, 23, 30 are for protection more than target of hunting of target shooting. Try a trigicon front sight and see. You can always add a rear sight later or some other type, like ghost ring which I have on my 30, just put the lit up dot in the circle and bang