There's a crosshatched area on inside of windshield for mirror mounting - why not mount directly on glass? I have to assume Buick engineers know what they are doing but I never saw this on previous cars.

I scrape windshield and mirror button each time with a new razor, prep and stick button. I let it cure for 24+ hours before mounting mirror back on.

I live in Texas and summer temps regularly exceed 135 F in car.