in doubt I went with the Qantas premiere platinum for which the 75sc are awarded after first spend (exclude ato gambling etc...) with the added advantage to count towards life time tally, unlike ANZ one.
Just spoke to Qantas Money on the phone and spoke to a supervisor who confirmed that QFF only backdates for flights. For bonuses through card spent, it uses the date it gets added to the account. So it's 6-8 weeks time. No go for me.