About the window tint, ya I know this is an old post but.... When I lived down south I had a car without AC and did some testing. Before and after window tint. Interior temps were dropped 10 degrees even with light window tint!
We have 2 wagons with lots of window surface area and tinting both really helped reduced the compressor cycling when the climate control is on auto. I don't have the FE numbers to prove it but it helps keep the AC compressor OFF more of the time. I wish the state would let us tint the front side windows too. I have to get a doctor's notice saying I have a skin condition. Also keeping the sunroof in the tilted UP position helps reduce the heat soak while parked in the sun.