Hi Thirty,
I've got a stainless bar from Finish Line and it measures 1.5" O.D. with a wall thickness of 0.185". The mounting hardware is a combination of weld on frame brackets from Everett-Morrison, and home made bar to frame pieces. The bar is 14" high measured from the center of the bar to the body. I took this measurment from a CSX4000 series car, if you are 6'6" you may want to go higher.....or end up 5'10" in the event of a roll over.
Good Luck!
Jon Miller