The part about tearing the camera back open and finding every screw hole full is what gets me. So the real question is, when did you actually stop and think "this screw came from the junk drawer"? Was it after the second teardown, or did it hit you halfway through the first one and you just ignored it? I've done the same thing with a spring that flew off a bench and spent 45 minutes on hands and knees with a flashlight, only to find it was from a pen that broke two days earlier. At some point you have to ask yourself why the brain always jumps to the worst case first instead of the boring answer. Curious if you had a moment where you knew but kept going anyway.

I read a thing from a cabinet maker who said biscuits are more about alignment than strength. They keep the boards lined up during glue up so everything stays flat and true. Once the glue dries, the joint itself is doing the work. His drawers stayed tight for 40 years because he clamped and glued them right, not because of the biscuits.