The paper really isn't _that_ secure. A large fire in a paper archive is only really a once every 50 years phenomenon, tops. Besides, look at the already-existing boring-as-hell absolutely-paramount-to-nat'l-security nuclear missile program to see the grunts running it will be easy social engineering targets. None of them will care.

Be careful with your wishful thinking.

You want a least worst escrow? How about an escrow where the keys aren't written down. How about you just restrict your salt to N, N+1, .., M and have the TLAs brute force it? Actually trust no one.