Thanks! I'm going to mark out the grid for the cleats on the hull then just snap chalk lines once the boards go down. Figure that should work. My boards are all going to be seamed on a cleat anyway as I want to retain the center hatch for fuel tank removal/access.Yeah, it worked well. Marking the deck surface for where to install screws to make sure they all hit a cleat took some head scratching, but I got it done.
Yes, I'd recommend pre-drilling your foam holes. Save the plugs and PB them back in place after the foam cures.