you shrink fit it to the out side, inside would be insane lol
you basically tint the out side of the glass, clear film side up. wet the glass and the tint, squeegee it it down. if a wrinkle forms, ( they call them fingers, cause thats what they look like) you hit them with the heat gun and wipe it down. they get smaller and smaller. so its like your tinting the window two times, once on the out side to shrink and trim to fit, then take the clear film off while its stuck to the out side still, wet it down good, wet the inside of the window, peel it off the out side of the glass and place it on the inside and squeegee the liquid out. work from the middle out pushing any air and liquid out to the sides. not really hard at all. just need to take your time and have patients.
i got away with no heat on the doors, but the brow and back window needed it big time. ever see that ricer with all the bubbles in the back window tint? that guy didnt use a heat gun lol and i lol every time i see that.