8 feet eh? You’ll be gliding forever on a warm day. 😁
At that wingspan though, you’ll definitely want some carbon fibre tubes to reinforce the wing. Foamboard is a little bendy and I imagine even a folded wing with not-the-highest aspect ratio will be a little floppy. But hey, you’ll probably be getting some carbon tube to make your tailboom anyway, so get some 10mm tube and you can use it on both. 🙂