Here are a few more pictures from this evening. The first shows the bottom and how it overlaps the butt joint on the lower part of the cabinet. This helps reinforce that joint that is holding all the weight of everything above it.
Then a picture of the front of the upper cab with the textured side panels in place. This shows how far back the panels extend to reinforce those vertical walls.
Then a shot of the final bit of work this evening. I took the spare motorboard that I blew up with the router and used it to test fit the horn. Now I can build the support in the back to hold that driver. Gotta love a wave guide that is as big as your head.