If you're not going to use all your segments anyway, then personally I would go for the blow-out CX F experience:

SYD-HKG-FRA (by train to Nuremberg and then back to FRA, I guess) FRA-DFW-<USA>-JFK-HKG-SYD

as the basics of it, which is fine so long as the first time through HKG is less than a 24 hour stopover.