Someone mentioned the height of the sight. My RMR stands .850" above the slide at its tallest point. The taller cowtiness sights are about .300" tall. It would be tough in my opinion to shrink the sight much more and still have a decent box to look through.
For comparison, my Trijicon HD sights are about .200" tall.
For comparison, my Trijicon HD sights are about .200" tall.