Fortunately I had these pics. I used a pice of 1/4 inch plywood for the mounting board. The pic with the board in the box shows that it is resting on a layer of sand before I covered them with sand.
If you are looking at the schematic, while viewing these, you can see where I tried to keep the components for each driver in some sort of order, with the woofer on the left , mid in the center, tweeter on the right, for the pic of the crossover in the box. The underside of the board is flipped left to right, and you can sort of tell that by the color of the wire ties.
For installation, I just removed the binding posts and crossover from the PT800, and ran the wires in through the holes where the binding posts are. So I could easily put everything back to stock, with no signs of molestation if I wanted to.
But I don't forsee that happening........