I'd rank it LAX, DFW, JFK.

Out of LAX - 40 AA metal J seats a day (2x788) and AA just does a bad job of selling J to Asia out of LA so it's always a soft touch on SWUs.

DFW next. 57 AA metal J seats a (772 + 788). That can absorb a lot of high LP SWU users.

JFK last. Only 30 AA metal J seats (1x 789). Plenty of cash buyers happy to fly AA. The AA flight is a goldilocks schedule, departs at civilized 10 am and arrives at 2:35 pm (only a little after midnight on your clock). Flight is pleasant on your biological clock and post arrival, you can nap, freshen up and have dinner at 8 pm if you want. The early afternoon JAL flight is just the wrong side -- you waste your morning before leaving, and you get in just a little too late to do anything on arrival day but go to bed.