I think less than a week is a bit short to find a perfect planet, and why must it be in the Circinus galaxy ?
I agree. And I would recommend using a galaxy with a unique model, because the Circinus Galaxy's model appears to the be the exact same as M 51.
Also, a word of advice, so things don't go wrong in your challenge:
Include a reference location, and ask everyone who joins to go to it and see if it appears the same way it does on your computer, so that you're sure everyone uses the same universe.