1. I have not done this which is why I am asking what the law is on it.Look Hulu. If a cop sees what he has reason to believe are over tinted windows that is probable cause to stop you. Should you refuse to allow him to check your tint with a light meter or a card then he will simply issue the ticket based on his visual examination. If you want to be an a-hole at the time he can simply say that the car is not safe to drive and impound the car and then he will have all the time he needs to test it.
2. Any criminal defense lawyer will tell you to never talk to the police and never consent to a search of your car.
3. Following the constitution does not make you an A-hole. Cops swore an oath to the constitution. This is not the grand inquisitional which people are required by force to incriminate themselves.
There was recently a vet who was extremely polite and courteous to a cop he encountered while traveling to visit his daughter in California. The cop stole the vet's life savings and I think left him with $10 stranded on the side of the road. The Vet did not even break any law to justify the stop to begin with let alone having all his monkey taken from him via civil asset forfeiture. I would ask who is the A-hole in that situation?
Lawyers who have watched the video said that the VET did nothing illegal but the only thing he did " wrong" was talk to the cop and allow a search of his car. I'll link you the story if you are interested.