aluminum sheet and then cover the entire tunnel down to the floor with vinyl. I mad simple bucks out of scrap wood edged with ¾” radius ¼ round molding and then bent the sheet aluminum to shape. The caps extend down the sides of the tunnel far enough that holes for the nutcerts can be drilled below the top chassis tube and avoid the use of velcro in that area. In an attempt to keep interior heat down, I plan to also cover the sides of the tunnel with bubble insulation, and then add some visual interest to the vinyl covering by placing a seam on either side of the tunnel top at the point where the cap begins to turn downward. Not sure yet if I will go through the trouble of doing French seams again, or just do a simple single stitch. I’m hoping that I can use the carpet snaps already on the bottom of the tunnel to secure the vinyl covering, but I may have to add a little Velcro as well.