"Much, much later...."
...Operation concluded with resounding success, thanks also to the tips in this thread. 8)
We had it double-boxed as follows:
- Plastic bag wrapped around the monitor itself
- Inner box padding: soft material protecting the CRT face, with layers of styrofoam in the corners and on the back, and softer foam cushioning for the monitor's sides (where there was less space available)
- Outer box made of double-wall corrugated cardboard
- Outer box padding: two layers of styrofoam protecting each side, and loads of packing peanuts to fill the space between them and the inner box
- Oriented the whole thing so that the CRT is face-down, with clear "this side up" markings, and loads of "caution, glass!" tape. Of course there's no telling if they *kept* it face down at any point, but I'd like to think it helped.
The thing spent almost 2 months in transit, due to holidays and pandemics conspiring to make shipping services even less competent than usual (tracking stopped working pretty early on, and the system never even showed it leaving Germany). But it did arrive, and almost to my disbelief the 5153 had suffered zero damage whatsoever. Not a scratch on it.
I guess they still gave it a good try, because the outer box had been clearly impaled by a forklift on one side, and drenched with water on another (at least I hope it was just water):
That forklift prong made it to the inner box too, but luckily didn't get past the padding inside. The idea behind the plastic bag was to protect against moisture damage, but it also nicely prevented bits of styrofoam from slipping inside the monitor's chassis through the vents:
And sure enough, it lives:
Third time's the charm, I guess. Turns out that these things can safely cross continents after all, so hopefully this info can help others in the future.