Thanks for the detailed and accurate instructions! My tiny contribution; the socket sizes are 11 and 14 mm.
I used 3/4 birch ply, and indoor/outdoor carpet from HD. Carpet is just tacked in place for this photo as I was checking for clearance around the edges. Also, the carpet doesn't have to be aces as the cargo mat covers virtually the whole thing up. Lastly, I am still contemplating adding spacer towards the second row as there is a couple large wiring harnesses there and I want to make sure I am not putting any pressure on them.