Here's a question I have that isn't related to this puzzle in particular.
Has anyone designed a logic puzzle whose central deduction is a meta-deduction? That is to say, a logic puzzle which is logically deducible only because you are foretold that is logically deducible, and therefore at a certain otherwise undecidable point, you are guided by such meta-knowledge.
I think there are Mystery Hunt logic puzzles that are kind of like this. Where for instance, the puzzle has a unique solution only because you know that a certain block of squares must be filled in such that it forms a valid Braille letter.
I'm not sure if using meta-deduction is even possible; the puzzle has to only have one valid solution, so at that undecidable point you could try all possibilities and see which ones lead to a dead end. Doing that is guaranteed to solve the puzzle, but never uses the meta-deduction.