In my climate that would cook things very fast. In mid-winter my hoop-house/plastic-sheeting setup hits 130F by 11am, so your technique is intriguing. the hightest temperature i've found in summer is my car windshield at 180F, but the pavement radiating & reflecting onto the home is about 140-150 for 3 months. the irony of my ness vs.my parentage of solar cooking & melanoma enthusiasts. wtf.