I have used an Mtac that is similar to the Crossbreed for two years now with an XD45c. It is very comfortable, but not for appendix carry....I keep it at about 2:00-2:30, so I can adjust it slightly to the rear when sitting. Keep in mind this is a full sized .45 semi auto, with long BBL. I have carried my J frame in an IWB Bianchi full size auto holster, and that puts the round butt just behind the belt...this works for appendix carry and is not uncomfortable, but it can be a bit slower to present the firearm from the concealed position. On the plus side, it is totally concealed, and a good BUG position for a J frame .38!
MW