Your rear glass rolls down. You can make it really dark and then roll it down at night while backing up if you need to.
I did 35% in the front (darkest legal) and 15% over the rear factory tint. So that makes it about 2% in the rear. 0.15 x 0.20(factory) x 0.70(auto glass) = 2.1%. People say factory tint is around 17%.
Is there an obvious difference between tint levels? Definitely. Does it bother me? Not at all since it helps keep the truck cooler. I do roll my rear glass and windows down when I am backing the boat into its spot at night or when backing into a friend's driveway with a LOT of trees. But the rest of the time, it's not a problem since I have the rear camera.
There's more pics of the tint here:
http://www.toyotatundraforum.com/int...th-llumar.html
I do need to go back and get the front driver's door redone. When I release the seat belt, the buckle hits the glass and there's a couple of spots where it's chipped holes in the tint. Guess it's good that I got a scratch warranty.