The hottest spot on mine was the plastic between the seat top and bottom so I attacked that first.
Pictures of what I did below. After a long ride today, my wife said it was much cooler. The surface was still 98 degrees at the end of the day but the temp on the insulation behind it was 136. So i figure I got close to a 35 degree improvement. I forgot to measure the temp before the project.
There's still heat coming into the cab - mostly convection not hot air. Thru the bottom seat and behind the legs. But todays ride was a lot more enjoyable than last weekend.
The problem is - that heat is released there by the header and has no where to go. I need to move where the heat is released and/or move the hot air. I think Bayouownbeer's idea may a place in my future to.
Materials: Dynamat 3/4 inch hoodliner, Thermotech Heat Barrier, Black Gorilla Tape
After the first test drive I felt some warm air coming from behind the back seat. Some 3/8 closed cell rubber tape stopped that.