16 of 240 done... decent progress on the next 14
I've got both the backing pieces cut, along with the zig-zag edging on one side of each of them. I also attached them to the lattice with liquid nailz. Perhaps it was a little overkill to use that over wood glue, but I wasn't entirely sure how well the wood glue would adhere to the marker board; it's pretty smooth and wouldn't take the glue like normal wood would (hah!).
I ended up buying another dozen (!!!) clamps to make sure the wood was aligned properly as the glue was curing. They aren't light, so it made it quite awkward to handle the wall while it was drying (I had to flip it over after gluing and clamping it to make sure that the marker board properly stayed flat against the lattice).
Here's the progress so far:
It's decent and pretty sturdy now. Before, it was a bit flimsy and I had to be careful where and how I moved it.
There are still tiny air gaps between the floor and the lattice here and there, but a little silicone or caulk will tighten all that up. I'm not entirely worried about it, because the aluminum foil will be covering everything up anyway.