The gun, like most .45's is heavy and bulky. I am a big man 6 ft 1 in at 230 lbs. I can conceal the 345 but after about 4 or 5 hours it gets heavy and it pull my britches down. I think that this is a problem with most .45's. I carry it IWB with a holster from Bladetech. I am very happy with the holster. I gotta tell ya. lead SWC's is the sweetest thing that I ever ran thru this gun. They are 200 grain bulets and load them with 5.4 grians of win 231. I shoot these at our local IDPA matches. For selfl defense I am using some Hungarian hollow points that are accurate. Work it out. I am sure you will find a good load.
I'm 5'10", 190lbs and I can carry the P345 all day long (and frequently do). You just have to have the right holster. I use a Crossbreed Supertuck, it's the only holster I've found that is comfortable all day long, even when driving my pickup. It will conceal very well, even under a tucked-in golf shirt.