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.

SC's implies Qantas FFP. Your itinerary looks like the AA Plat non-challenge would be a wise choice.

It looks OK assuming that the last trip through HKG is a transit also... your two stopovers in Asia would be the PEK/HKG one and the CTS one (assuming that isn't just a mileage run).

Correct (and thanks). The needed stopovers are PEK and CTS. The HKG visits will just be <24 hour stays.

That's a tough call. This itinerary will achieve 1640 QF SCs. That will requal WP for me without a problem. I tend to blow my QF points on D to Z upgrades on QF long hauls (eg JFK-SYD as I did last year). That makes the QF FF program a winner for me - even if it comes at a premium price.

Once you re qualify for QF Plat the SC's are wasted and miles are only worth 50% compared to AA. Look at the AA miles (no $$ surcharges) required for F/Z SYD - JFK and compare to QF: ticket cost plus fuel surchage plus QF upgrade points. Big disadvantage of AA in Oz is not being able to put credit card points to the AA ffp.

AA must hand-write tickets with more than 16 segments (including surface ones). But it should be eligible to be an e-ticket (surely HEL has fixed their non-AY e-ticket processing problems by now?).

Do consider that the cost of a first class r/t award ticket on QF using AA points from SYD-JFK is only 145k miles whilst a r/t upgrade from D-Z costs 120k QF miles

Dave

You can launder miles from AX to AA via SPG.

Dave

Shouldn't be a problem anymore in HEL, but be aware that HEL-BCN is all-economy-flight these days.

AA and CX share the same office in BKK.

AA's system is just incapable of issuing anything more than 16 segments automatically. But CX's system should be able to and probably into an e-ticket too.

Moving on now the itinerary is developing / evolvong - 2 questions:
1.
I'm considering AA JFK-SFO as part of a DONEx ticket. Some flights seem to have First and (WH)Y only whilst others seem to have First, Business and (WH)Y. I'm following recommended practice in making as many segments "OPEN" as possible, so, given that DONEx books into A if there is no D offered, will this cause a problem for an OPEN ticket (flights will credit to QF FF). I suspect I may need to have a flight number on the ticket so I can lock it into A class - otherwise the nice CX ladies in BKK may insist on writing the ticket into D since some flights offer it.
2.
I look like having an arrival into LGW in the afternoon and a departure from LHR about 23 hrs later (ie next day). Is this still classified as a transfer or will I be slugged as a stopover?

Transfer. But if the coupon is open and the airline(s) change the schedule by a few minutes, pushing the stay over the 24hr mark, you might have to pay (I always date borderline coupons).

Recommended by some, not all, by a long shot. Old argument, anyway, with winners on both sides of the fence.

Fully agree; my experience with the DONE4 I have nearly finished is that it is so simple to change flights that you are better to use the 'free' insurance by booking actual flights where possible.

A 'phone call directly to the airlines involved (BA/QF/AA & CX) enabled several seamless changes even though I had a 20 coupon paper ticket. I only had 2 open dated DFW/ANC segments with the original booking (August, the actual flights were not entered into the GDS's until November).

None of these changes incurred any additional cost other than the 'phone call.