Two-Tall! Meshmixer made quick work of joining 2 parts. The thickness is 18mm. Be sure to rotate them so they are "back to back".
As a battery box using the foil strip for termination, a 2P or 2S configuration is easy to terminate. The slots are aligned in this orientation.
Installing a pair of cells in one housing lets the cells share the spring load. The contact plate will tilt some to maintain positive pressure on all 4 contacts.