I will point out, however, that the DONE4 price ex-USA is currently $8922 plus tax and license, while the price ex-NRT is (today's rate) $6056.

If you could invert your Oz/HKG legs it would most likely be well worth your while to fly to NRT one way (or half a long-term RT) even using miles + copay for J if needed, buy your DONE4 there, then go NRT-HKG-Oz-Europe-N. America, thereby enjoying 6 flights with up to 6 stopovers (instead of 2) in NA in the next year, before having to fly back to Asia (YVR-HKG on CX? O the suffering...) to finish up.

A $1000 RT ticket with a $300 copay still puts you something like $1500 ahead.