I've been slowly cutting the materials to size for this project. I came up with a cookie cutter way of cutting all the holes in the manifolds where the absorber tubes connect. I found a metal can of the right diameter and sawed the end off so I can twist it down thru the foam board and remove a plug. It works fairly well. I have to use a blade to finish the cut on the foil on the other side. Here are some practice cuts.
And the tube fits well.
