Your reflective shade cloth reminds me of something. IIRC, 1st generation Land Rovers (the ones inspired by the WWII Jeep) had an optional special tropical hard top. It featured a second layer of metal about an inch above the top, open all around the edges. This shaded the roof, making it cooler before auto A/C was common. I can recall looking at pictures of them somewhat enviously, driving my '66 IHC Scout 800 in the summer heat. I thought of trying to rig up something similar for the Scout, but never got around to figuring out anything.
Jim, "All of us could take a lesson from the weather. It pays no attention at all to criticism."