This is an option I’ve been throwing back and forth for some time.
Which is the best way to go?
-Suppressor-height sights with the RMR mounted in between the front and rear sight with 1/3 co witness.
-Suppressor-height sights with the RMR mounted in between the front and rear sight with ABSOLUTE co witness.
-Get rid of the rear sight and mount the Trijicon RMR in it’s place.
For ME, I prefer the suppressor sights in their normal positions (RMR between front and rear sights).
Having no BUIS at all, is going to make it VERY annoying when trying to pick up the dot; the whole RMR’ed pistol concept has a learning curve as it is; its bad to make it worse by having nothing to index off of when presenting the pistol.
As for co-witness - the suppressor sights really only come in one height; that’s all you can do to “control” what kind of co-witness you have. I haven’t seen any that are tall enough for an absolute co-witness, FWIW, but I could be wrong.
My Glock 21 Gen 4 has a lower 1/3rd co-witness, FWIW, and I’m using AmeriGlo Tritium suppressor sights.
My setup-
Glock 21 Gen 4 w/ factory threaded barrel, Trijicon RMR (RM05) and AmeriGlo Tritium suppressor sights. Its one of my hosts for my Osprey 45. 
