I tinted my front windows with 35%. Legal in Mass is 30% I think. A buddy and I did both of our trucks in a couple hours from start to finish. It was pretty easy. I was surprised, because it was my first time ever trying something like this. Definitely keep the window and the tint wet. Don't worry about getting your interior wet. You will have to re-armorall afterwards because the interior vinyl will get a little spotty. Good luck. Let us know how it comes out.