The problem with JAL F for me, booking thru AA, is that there is very limited, if any, A availability that I can find to book. Since I live in Asia that has limited me somewhat.

Here are my three example AONEs starting in Tokyo from the last year:

Routing 1 - AONE4
HND-HKG(CX F) / HKG-LHR(CX F) / LHR-BAH(BA F) / BAH-DOH(QR F) / DOH-LHR(QR F) / LHR-MIA (AA F) / MIA-BOS(AA Domestic "F") / BOS-LAX(AA Transcon F) / LAX-HKG(CX F) / HKG-SIN(CX J) / SIN-SYD(QF F) / SYD-MEL(QF J) / MEL-HBA(QF J) / HBA-SYD(QF J) / SYD-HND(JL D**)
**I booked this in D, could never get A availability despite ~6 months of watching and asking regularly, the route always showed A2 at least, but JAL never let AA book. In the end I changed to QF SYD-MEL-HND in J for better dates, but did miss my JAL business.
What did this give me: I nested a return from the Middle East back to Asia, which gave me another holiday, then it was designed to let me try QF F (first time, good, but no Wifi) and then obviously I had the maximum 16 legs by the end, but I also got to fly on AA F (Still not worth it, it had been five years and didn't seem to have gotten better, but I wanted an alternative to "another BA F flight").​​​ Australia is obviously not a good destination if you want F unless you do a fly-in/out

Routing 2 - AONE3
This was almost entirely designed to maximise my BA TPs under the old system, whilst doing a weekend trip to the UK back to Manchester

HND-HKG(CX F) / HKG-DOH, DOH-LHR(QR F) / LHR-MAN, MAN-LHR (BA J) /LHR-JFK (BA F) JFK-LAX (AA Transcontinental F) / LAX-HKG (CX F) /HKG-KUL(CX J) / KUL-NRT (MH "F"/BusinessSuites)
I did this, excluding the Tokyo legs, in about five days. Gave me a chance to try MH BusinessSuites (pretty good actually), however my LHR-JFK flight was delayed by ~3 hours which meant it was a bit of a rush to get my Transcontinental

Routing 3 - AONE3
Similar to the above, and a month later, so I just went the other way around the world, the start was the return MH BusinessSuites flight returning above. However I flew out on the day LHR burned down.... oh dear. I am putting in what I'd booked as TP maximisation, not the end result which ended up missing BAH and having an 8 hour flight to nowhere out of LAX
NRT-KUL (MH "F"/BusinessSuites)/ KUL-HKG (CX J)/ HKG-LAX (CX F) / LAX-LHR-BAH-LHR (BA F) / MAN-LHR (BA J) / LHR-DOH (QF F), DOH-HKG (QF J) / HKG-BKK (CX J) / BKK-HND (JL F)

Overall
If you reflect on these examples you will observe that "too" many legs are short, or in business. But it worked for me and I was happy with all routes. Getting pure F routes is hard unless booking well in advance, and with the AONE4 I wanted 3 seats (not always possible). I would personally try to make sure you get CX long haul (across to the USA or into Heathrow) as that is really special. Qatar Airways F is "ok", you've got the right idea to prioritise the A380 around BKK over the old Qatar Pacific F into HKG and sometimes MLE/others as it is a bigger cabin and more QR specific. I would not spend much time on either BA or AA F, however unfortunately BA has by far and away the largest network of F seats in oneworld, so you are going to have to do them across the Atlantic. The AA Transcontinental is worth doing before they get rid within a year, but certainly nothing to write home about - it is obviously better than a domestic F flight. And then finally, you will struggle to really get to anywhere near 16 legs if you are doing only an AONE3, you'd need to add in at least Australia (only QF F available) to get some more routes. Personally I'd rather do CX F as my trans-pacific flight which means HKG (since JL F seems impossible to book) over QF F, but then you can only get QF F in and out of SIN (is there now a JNB option?). Finally, when you get into IRROPs, whist they will obviously treat you well, you get into the simple situation that most F cabins now are full days or weeks out, so you really do get stuck being bunged back into business.

So, now that BA has made "A" earn less than "D" I am even less tempted to book another AONE trip as the 30-40% premium is hard to justify objectively when you end up with 30% of the flights not really being in F. But, they are special otherwise.