QF speak is bigging it up of course but reports that payload will be around the 156 pax mark
the WA market simply does not add up and if you want to transit and go on it means a change of planes at PER - checking in again and then a short or mid-haul flight for another 4-5 hours to where you really want to go does not make good marketing sense
also i read that the new variant of the 777 coming along should be more suited to a non-stop kangaroo route from UK/Europe which could include MEL and not just PER