I used one layer of the thicker variety of heat shield. 90 mil I think it was. And I did re-apply the foam inserts back on top of the heat shielding in their original positions. Adhesive aerosol spray works well for this purpose. As far as tips...just take your time and cut it to fit well into all the nooks and crannies of the panels. Takes a bit of time, but your results will be better.