Hey y'all, rookie award traveler here. I'm planning a trip to Australia in March-April 2023 and would really like to snag a biz seat, but I'm very aware that such routes are considered unicorns. I only have about 200k miles to work with, so originally I had resigned myself to purchasing cash economy and upgrading to PP with miles... But the waitlist method seems too tempting not to try. My fear of course is the high risk-reward. Getting kicked back to economy would be a real letdown on my first international trip (plus I suffer from chronic back pain, so 15 hours at 4" recline would be a nightmare...).

All that said, what's the best way to "guarantee" (as much as one can) at least a slot in PP if the unicorn eludes me? As I understand it, there is no such thing as "saver" PP - I've only ever seen 170k awards for SFO/LAX-SYD listed on the UA site. Are there any options to waitlist for PP at a lower rate? If not, is it possible to upgrade an award ticket with cash? And does anyone have insight into how much that would cost if so?

Thanks in advance for any help. I'm still getting my feet wet but this stuff is addicting - like gambling but less financially damaging!

Edit: I don't have status, but I do have a Quest credit card, in case that is important.