I'm 6'0" and 220... large frame, but really not much in the spare tire area. My absolute favorite holster so far is High Noon's Tailgate tuckable IWB. Mine's for a Steyr M9-A1, a medium framed double stack 9mm pistol. It conceals fine under cool weather clothes. Hides fine under just a t-shirt if untucked. Tucked t-shirt is tough.
Been meaning to post pics and a review of the holster. Brown Santa brought it just last week after a 6 month wait. I really like the holster. It's WAY more comfortable than the old kydex job I had been using.
although i cant really get away with only a tucked in shirt, its great with an un-tucked shirt or any kind of light jacket. super comfortable and has a couple different mounting holes for the clips, to customize the depth.
I've had luck using a leather DeSantic IWB holster, but at 5'8" and 120lbs, I'm a far cry from being a big guy. My guess would be that a good leather IWB would work well enough, but you may want to bump up a waist size on the pants to prevent the pants from feeling too tight.
Between 4 to 6 o'clock it does not pinch at all. This is my preferred carry mode. The butt of the pistol tucks right up against my body parallel to the 12th floating rib. If you hunch over the pistol may print, so sit with good posture and you'll be fine. Drawing while seated is easy: just lean or scoot forward one handwidth from the back of your seat and reach.
Between 3 to 4 o'clock it doesn't conform to my body as well. The butt of the pistol goes straight aft instead of following the curve of my body. Sitting doesn't cause a pinch, but if I twist my torso or lean to the right it does pinch. Drawing from this position, especially while wearing a seatbelt, is awkward.
Appendix carry: the Steyr's a little too big for me but I'd be willing to give it a try with a slim compact.
You've motivated me to take some pics this weekend. Will follow up with more info later on.
Im 6 foot and 220. I carry my Stoeger Cougar fullsize and my Steyr M9 in High Noon Holsters. I have the Mister Softy and carry it fine summer and winter. If you had a big gas tank for the love machine(beer gut) it could be uncomfortable to sit down and drive. I have lost a few so thats not an issue with me.