Great pictures. After you cut a piece of wood to fill the hole under the shower pan, it's fairly easy to improvise a couple of pieces of wood to hold that piece in place. As I recall I used 5/8"plywood. I did make it so that it was easy to remove. No one I talked to at Thor knew why the cut out was so large, possibly to accommodate a different shower pan or make installation easier. I told them to fix it, but I don't think they listened