Are these the cities you really want to visit (ie New York and Los Angeles)? you could bet better use of 26000 miles in SC's and QFF points using some other ports. But its not going to make a huge difference.

If you don't have a lot of QF points now, nor any QF status, you might like to consider doing the AA Platinum Challenge. You could have OneWorld Saphire status during this trip, and AA's program earning and spending can be attractive, especially for someone in Perth. For example, its 20,000 AA miles for an economy award anywhere in Australia/NZ, or 35,000 miles in business class.