On the rear of the opening, there is just enough room to attach a peice of #16 ga. sheet metal to the tubes, that won't actually show from the outside, with 3 self tapping screws (it will be hidden from view by the top material when viewed from the outside). I would weld two short 3/16" threaded studs that stick out toward the inside of the passenger compartment to the side of the 16 ga. That way, I can first set the lexan in the cab, then open the door and get in, then slide the lexan into the channel at the front and over the two studs at the rear, and put a couple of wingnuts onto the studs to hold the lexan in place. I would possibly have some foam rubber glued to the bottom edge of the lexan to fill the gap at the bottom and keep a bit more wind out. This would probably be as awkward as a monkey making love to a football, but it would only be done at the beginning and end of each day (and during pee breaks). Again, when the trip is over, it can all be removed leaving only 3 small threaded holes in the frame tubes.