Interesting topic.. Wel on modern automobiles where the black fret hides the glue, I'd say mount from the outside, just as per OEM. the location of the weather strip (on the clear or on body) hmmm, dunno which one would be better/easier to paint/mask On vintage (pre mid '80s) I prefer from the inside, the thickness of the pillars can be hidden somewhat, when one designs the clear with a precise fit (taken into account paint thickness) to the surround (windshield or backlite opening) but with a small almost "flash like" flange, (I think with current CAD technology a lot is possible) as a positive locator, glue surface on the inside.