It seems like a shame to sandwich wood between chrome-moly steel and aluminum. Will it be cedar or redwood so it doesn't rot out? Possibly you could shear the flash metal into strips and bend them into mullions.
Wood or aluminum, if you lay them out like the deHaviland Mosquito, the flash metal could be cut into larger [diamond] pieces with fewer seams.
____
At 66x21" and 1/3rd scale that's only a 15 1/2x5 1/2' vehicle. Maybe it's 1/4th scale?
At 1/2 scale it would be the size of a Lakester belly-tank.