My truck weighs 5500lbs completely loaded with rockwells and 42's. Its a 77' f-250 and i'm about to start the cage. I know to use DOM for the main hoop, halo and ?A bar? but should i run 2" or 1.75 and if i run 2" could i run 1.75 for the front and the back half is already 1.75? How do you weld all they way around a joint near the roof if the roof stays on? I've got my flame suit on.