Method for Creating Any Unambiguous Grammar?
No, and there is indeed a reduction to the undecidability of ambiguity.

First, note that ambiguity is (for context-free grammars) semi-decidable: just keep generating words by different left-derivations and say "ambiguous!" when you first find a word you've seen before.

Now, the method you are proposing allows to semi-decide unambiguity. You effectively look for a computable enumeration of all unambiguous grammars. You just generate grammars until you find your given grammar and answer "unambiguous!".

Since semi-decidability and co-semi-decidability imply decidability, this contradicts what you already know. Hence, there can be no "set of rules" as you propose.