I've built two U3S's and the part density makes it quite a challenge for this old-timer, I feel your pain with the small gauge leads on the resistors. For an enclosure, buy a 3D printer and print one of the several QCX enclosure designs on Thingiverse. I recently started playing with an Ender 3 Pro printer and made a box for the QLG GPS module.
--
John, WB5THT