cas - Every time I gain weight, I realize that the weight I'll finally be happy with gets higher and higher. I too will one day have 20" guns and be 280 lbs.
I'm not sure I did the waist measurement right. I measured right around my belly button, so maybe I just measured my stomach. I wear 36 inch Levi's Silver Tab Baggy jeans and they are a bit baggy in the waist.
Bone size and density plays a large role too. I remember the first time my chiropractor took my x-rays. He called me back 2 days later to take some more because he had "problems" with the first ones. Same result on the 2nd ones. He showed me my x-rays compared to a normal one. Mine were at least 50% larger and more dense than what he showed me to be a "normal" x-ray of the neck and spine.
I really am about 250lbs of just bone...with 35lbs of muscle.