I have been carrying almost daily in a SmartCarry since June 2003, and have never been made. I'm a big, big fan.
My clothing of choice is shorts and a t-shirt, and I'm 5'8", 185ish.
The one position that doesn't work very well, especially with a belly, is sitting down in a car. (The inventor claims otherwise, but he's a beanpole!)
I have a holster stuck between the front bucket seats, and that's where my gun goes when I drive. Before I get out, I tuck it back into the SmartCarry. (This should pose no problem at all in the cab of your truck, since you're so much higher up than the rest of us).
The inventor of SmartCarry has a patent on his design -- claims that it is better than Thunderwear because there are no seams for the gun to catch on during the draw. I have no idea -- I've never examined a Thunderear rig up close.
Oh, and folks: It is a holster. It just isn't yours. So lighten up!