Here are a couple of photos from when I installed mine. The piece that goes over the center hump has triangular cutouts in it that allow it to be folded and stapled together at the top to make it match the shape of the cab. The rubber plugs that secure the insulation to the firewall are a real pain to get through the holes. This tool would likely make things much easier. I have not used one.
https://www.classicparts.com/mobile/...ctinfo/42-080/