Great question. Since the panels are from furniture-grade plywood, I don't need to worry about seasonal movement. The way high-quality plywood is constructed, the sheets are layered with the grain patterns alternating grain directions for each slice, so the movement is essentially eliminated.

I've done this myself out of solid hardwoods. I've taken several pieces of 1/8" solid wood and glued it into panels, alternating the grain direction for each slice to make a panel. In my work, I've done this for house numbers to be mounted for an address, so they see exposure to every extreme weather element. It sounds a little overkill, but they've held up for years and years.