I don't own a G19, but that'll be my next buy, if I ever buy another firearm, providing, of course, that I can find a killer deal ftf. However, I do carry a G26 daily and own several other Glocks.
I don't carry a light with me, nor is there a way to attach a light to my G26, so I do use night sights. Also have night sights on my nightstand G17, even though I do have a light attached to it.
I can't stand the feel of nekked plastic in my hands, so I install Agrip on my Glocks, with the one exception being that I installed Wilson tennis racquet grip tape on my G17. I also can't stand the feel of factory Glock trigger connectors; accordingly, I install aftermarket connectors on all my Glocks. I polish all the mating surfaces in the firing mechanisms, using a Dremel on its lowest speed, Simichrome, and a soft polishing pad.