This is what evolution led me to. My son just broke the first box, which I designed to replace the original one. Now the newest version should perform better, super sturdy, rugged, whith improved, reinforced hinges. And, of course, had to look cool, too...
So I came to the actual F117-inspired design. 3mm walls, just big enough to fit his braces. Check the PDF to see if it applies to your needs. You won´t need any brims nor support, just check the rotation of the parts in your slicer, lay them flat with they hinges up.
You need 2x DIN912 or similar M3x16 screws, V2A steel recommended to avoid stain. Show me your makes! :)