The legal limit here is 30%, they tolerate 20% all around, and usually 5% on the backs just depends on the cop and his mood for the day. According to actual law (its not really set in stone for suvs/trucks) 5% is against the law. I'm thinking if I just go with 20% all around I'll save on future headaches and I wont have to worry about 2 windows being considerably lighter then the others.

BTW, when I learned to drive I never flipped the rear view mirror up at night. So, I've never done it and probably never will so that's not an issue for me