thinking for #nexum (the sync tool for Linux i'm starting to work on) i'll make the "pair codes" consist of diceware-like strings
10 words gives ~128 bits of entropy, which should be more than enough -- a v3 onion is 280 but we can just pad it or something :P
so, say, the device would show like "most members saturn fool food letter than along alabama land", which you would input into the other machine(s)

