I used large self-tapping screws, about a foot apart, around the perimeter and down the middle. I laid out e-track on the floor so that the outer edged of the e-track were 48 inches, and then installed them with screws about every foot, as well. Then measured the interior between the inside edged of the e-track, and cut the 4x8 foot plywood to fit in between the e-track. I have 9 feet of cargo space, which meant I had to add another foot of plywood to the deck, added farthest from the rear doors, then filled and sanded the seam.
Decks in cargo vans are subject to a lot of skids being scooted and dragged, so the decking can take quite a beating with all the scars and scrapes. Many people flip theirs after 6 months, then after another 6 months they replace the plywood. I gave mine 3 or 4 coats of Minwax Polycrylic, which not only protects it, but makes cleaning it very easy. Oil and other stuff won't seep into th wood. Instead of flipping mine every six months, I add another 2 or 3 coats of Polycrylic. Mine is still going strong after more than 3 years. I did have a forklift operator somehow manage to slide a fork into the edge of the plywood and take out a chunk the size of a dinner plate, but regular ol' automotive Bondo, a power sander and some more Polycrylic fixed 'er right up.
The old Ford E-350
The new-ish Sprinter
). A 2x8 prevents freight from sliding forward off the skid.
