In non-DansDeals Forums language, he used United miles for the roundtrip on 2 separate occasions. He then gave a tip for getting First class availability, but I think we're still a few steps behind that here.
I love the translation, @Yehuda!
But seriously, OP, hang out here for a while. There is a lot to learn.
When is your trip? If you have a few months, then if I were you, I would open a United and a Sapphire card from Chase and maybe an Ink as well. I would do all these aps as a multiple browser method. (You can look that up.)
If you have a Red Card, then in one month you could have enough miles to go to Australia and back in first class.