I installed 10% mirror tint on my camper windows.
Its extremely reflective
So much so that if the sun is in the right spot in the sky, it'll blind you pretty badly. And you can feel the heat its reflecting.
Its a pain to install, but it really cooled down the inside of the camper. Its basically like a 2 way mirror. You can see out, but unless its dark out and all of the lights are on in the camper and you get right up on the window, you can't see in at all.
I am super happy with how it turned out.