I've carried a S&W M&P40 full-size in an IWB before with little issue on printing. Here in NY it has to be completely invisible, i.e. no print, and I've had full confidence with it. However, over the summer I usually switch to a 3" 1911 with a compact grip.
With an IWB, the big concern is the grip, and I find something with an "FBI-cant" to it usually makes it easier. I can't speak on the King-Tuks, but try the Galco 'Summer Comfort', I used it for my M&P and had no issue covering it up with a light button-up and jeans. I've also never used one, but heard good things about the Cross-Breed holsters, which I think the King-Tuk is modeled after anyway.
Also, if you've never used an IWB before, you may need to modify your attire slightly to accomodate it. If you wear tight jeans and tight belts, might need to get a couple new pairs to handle sticking a gun in there, lol.