I just went to Home Depot or Lowe's and bought a roll of the aluminum bubble looking stuff (about 1/4" thick) in the insulation aisle. Really cheap. Then, when I went to install it in the cab roof area, I cut it a bit larger than the metal surface area and stuffed the excess iinto the crevices around the windshield, door frames and over the roof headliner brace. Didn't use any adhesive at all and installed the cardboard headliner. Doesn't bow or droop at all. If I need to get it out in the future (read mice) no problem.
