IMHO it is better to use all the points to redeem business class outright rather than upgrade. That’s the only certain way to ensure you have business class seat.
Qantas’ a’ upgrade system is like lottery. Basically you apply for an upgrade and you hope you will get it. The problem is, it depends on how many people are competing with you for those seats and it also depend on your status with QFF. If you are platinum one and traveling on mid-week on low season on a unpopular route, you have a good chance. But if you are poor average bronze like me and traveling on Xmas heading to London, you might as well forget it, your chance will be poor. Also in order to upgrade, you need to purchase the most expensive flexi fare which can easily cost >$3000 rt to Europe. If you don’t get your upgrade, you are stuck in economy for 22 hours with a very expensive fare.
As to how you can get the extra 200k miles quickly. The quickest way is to sign up credit cards. However, do not sign up too many credit cards within a short period of time as it can really damage your credit score and it takes up to 5 years to recover.
If you do go this route, there are some cards that offer very good sign up bonus at the moment. Amex platinum charge card offer a whopping 100,000 point sign up, but also a whopping $1200 annual fee.
Other ways to do it quickly, especially with your ANZ QFF black card, is pay tax to ATO using your Amex. See if you got any friends or relative who has a big tax bill to pay. ANZ still award full point earns on ATO.
Other ways you can do it, if you have some cash spare, is to open a Bankwest QFF saving account and put some money into it. You’ll earn 12 points/$100 per month that you put in the account.
Last but not least, is to find out if you have any family members that has some orphaned QFF points lying around. You can do family transfer for free online. Selling of miles is against the T&Cs of QFF, but you can always buy them a gift as a token of appreciation.
I’m sure others have other ways of earning QFF points quickly. But whatever you do, avoid over spending on things you don’t need just for the sake of points.