Obviously you have not try it in Florida. We have the flimsy stuff aftermarket POS one below our glass on the Model Y, again nothing compares to the automaker's insulation (embedded into the roof like on our Maverick). Theory dictates you need insulation but you need distance, like when they...
I would not hesitate if they give the option as of with ventilated seats for Y & 3. South Florida heat is unbearable My Maverick cabin is extremally cooler then our Model Y. Glass can supposedly block 99% of UV light but remember the UV light transform into heat onto the glass as infrared heat...