I will be using 1.5" OD tube for the lower front stuff (windshield protection, light mounts, etc) and 2" square for the rack above the roof, I think it's .120" wall. I have no aspirations of using the turret hole and I do intend to incorporate some sort of fairing to the end result. I also intend to have a winch crane mount on it as well, as I have no desire to actually carry anything up a ladder to store it up there.