My advice, use your free entries in the Lunar New Year challenge and then leave it well alone!
Teams are evenly matched (from what I can tell), so you're going to have tough matches right from the start. I quite like that, but the problem is you have no idea who you're going to get so you have no opportunity to set your team up accordingly. End result, you're going to lose as many as you win, so spending anything on it seems like a bad idea.
Seems to be a lot of red cards and injuries too, but that may just be me.
Teams with mutants may fair better, would be interesting to know.