I own the Kahr PM9 and don't consider it to be a pocket gun unless you have large pockets. The Kahr P380, Ruger LCP and Sig P238 are much better classified as pocket guns. IMO, your best bet is to try and rent the guns and give them a range testing. I'm not a big fan of a safety on a pocket pistol, so I wasn't interested in the Sig P238. I do own a Kahr P380 and Ruger LCP and find them both to be very good pocket guns.
The other alternative is to look at a S&W J-Frame revolver.