I was interested to see the profile of the shadowmask holes. I had always assumed that they were, well, just holes. The different size and profiling of the etching from each side, to avoid stray electrons bouncing down the 'length' of the holes, is really clever. Real attention to detail.
I once pulled a shadowmask out of an old tube. The mask itself was incredibly easy to dent with even a fairly gentle touch, but I was surprised that the frame could be held so firmly (and presumably repeatedly) by the bimetal strips onto the mounting pins in the faceplate, very good tolerancing. Also the hand applied foil shielding to prevent stray electrons from leaking around round the outside of the frame.