The Galco Kingtuk is a pretty comfortable IWB holster. I use one now to carry my all steel full size 1911. I plan on getting one for my M&P9 FS soon so I can put it in my carry rotation.
With any holster a good belt is a must! leather ones are kind of expensive so I opted for a nylon web belt. this is what I use now and I'm very happy with it. Cabela's: Uncle Mike's Sidekick Holster Belt
cleveland Holster for ITW. (supertuck without the superprice)
very comfortable for my 9c.
Not sure about full size but I can stand, walk, ride m/c or drive truck with it no problems. Cleveland holster is 1st carry ever that I can say I am 100% satisfied. ( and I have a closet full)