@Kira: I have a feeling you will be exploiting a hole I seem to have overlooked. Your risk is great, but so is your gain. Patience might be in order, depending on whether or not I am on the receiving end of a blue falcon. Do you travel east? Do not acknowledge this message.
ZORI
If 3, ?ORI is proved by letter change from HORI to ZORI, but no score change.
If 2, HOR? is proved by score decrease whilst the only letter change is H -> Z
CORE - ?
If CORE - 1, ?O?K is proved by score change from 2 -> 1 while CORK -> CORE (only letter change is K).
If CORE - 2, ?OR? is proved, since CODE - 1 (where ?O?? is known) means that C??E is incorrect.