Brent,
Do you have Murray's contact information? I might be looking for some correct 11/16" plywood floorboards. I think most plywood floorboards sold by model A vendors are made from 3/4" or 23/32" plywood. By the time you install the webbing around the edges, they are a little to high. The planked floorboards I made took a lot of effort to make. I don't know if it would be worth it again. If I could find the correct 11/16" thick hardwood plywood, I would probably make them myself.
BTW, I think we purest are probably over building the planked floorboards. I have seen many floorboards that have very uneven wood planks in them. Look at the floorboard below.
Rusty Nelson