Re: QANTAS minimum hours.
Having gone through the process fairly recently, this is how it panned out for myself. Apply it to your situation as you will.
Applied the day my 500 command hour ticked over. At that stage multi time was non existant and TT was about 650.
Was told to update 12 months later.
I updated regularly throughout the next 12 months, and when I did so on the month I was advised to do so, with about 250 multi command and 1200 TT, was given a testing date within days.
I honestly dont think there is a steady rule. Was a fair backlog when I joined the cue so i think that protracted things a bit. Why don't you just give it a go and see what happens?