Once I get beyond pocket size and go to IWB, I prefer a gun that allows me to get all my fingers on the grip frame. The mini-Glocks don't work for me, but a Glock 30 with the flush fitting 9 round magazine works. The Springfield XDs with the 5 round magazine can accommodate all my fingers as well. I don't know about a Shield because that remains a mythical gun in my part of the world. Of course, you can carry small guns with a finger extension on the magazine and take care of the problem or carry an extended magazine for some guns like the mini-Glocks, Sig P938, Beretta Nano or XDS. One important consideration for belt carry is that being able to establish a firing grip on the gun while holstered. Some tiny gun/holster combinations preclude that. Good luck with the search.
