The clue is indeed perfect.

You have interesting criteria for perfection. :) You didn't consider my interpretation about the wormhole to be perfect at all, arguing that the GM would hardly devise such a logical path, deciding to link the clue to the avatar of Yashur. But here, the GM's path would be: "National Park" in Ment's profile ---> some random national park in Cuba ---> Che Guevara landing there among other revolutionaries ---> a random quote from Che as a lead. Isn't that significantly more likely than with the stars and the wormhole?)