I'm proposing the following itinerary:

BKK-HKG-JFK-MIA-CUN-DFW-YYZ-LHR-FCO-HEL-BCN-LHR-SYD-CHC-SYD-ADL-SYD-PEK-(surface)-HKG-CTS-HKG-BKK

First HKG visit is a direct transfer.
LHR-SYD will be single plane through service (eg QF2).
Can anyone advise if AA (BKK) will only issue 16 segment tickets? If so, then I'll have to go through CX (BKK) instead.
I know that SCs and miles are not maxed out, but the itinerary gets me where I want to go.

Any comments or suggestions welcome.