Hi I'm looking to purchase flights from Sydney to Seattle (return) for two weeks in August (have to be there August 15) and then join the waitlist for an upgrade to business class using miles+$. Wondering what flights I should bid for. I'm wanting to book for Saturday August 8th 2026 from SYD to SFO and return Sunday August 23 2026 from SFO to SYD as the economy seats are the cheapest these days. I've read that Saturday is generally lower demand for business class so better chances. I've enabled expert mode and there are 0 under PZ or PN but is there another fare class code I should look for? Thanks in advance for any advice. Also does it make a difference to request the upgrade at time of booking the economy ticket or can I do that later without consequence?