I used an Alien Gear for my PPQ until I mounted a light on the pistol. Now I have a customer piece made by HP Clayto that I can convert to IWB if I need to.
I recently started carry my Glock 20 in the same position the 19 is usually at; 4-5 o'clock in a Galco combat master.in the winter my usual owb carry doubles as concealed carry!
I carry my G17 in a crossbreed supertuck deluxe. It works for my G17 and my G23. I put them on a the 3 or 4 o'clock position. Both are comfortable to carry if you size your pants correctly.
G21, nylon DeSantis with clip(N52 I think). or OWB: Tagua thumb break pancake style. Also like a 1911A1 in a Bianchi Black Widow belt slide, or a no name leather IWB with a clip on, and a sweat shield, similar to a Don Hume. It works for me.