One of my Fraternity Brothers is a big guy as well and he conceals a Glock 22 just by ordering big and tall sized shirts online and let's the shirt tail hang out.
I actually did that too, cause I'm on the tall side and prefer a longer shirt for concealing when it is 95 degrees in the shade.
NRA Life Member
Big Sister: "You should be sponsored by Allen"
Me: "If you can't shoot good, at least look good walking to the firing line."
Big Sister: "Can you not afford a Pelican? Then buy an Allen gun bag."