777-300ER range?
Trimotor you should know the answer to this one;
OMDB-KJFK (great circle route) 6849Nm
-YMML 7231, YSSY 7481, KSFO 8103.
The optimum route (very lonely over the Southern ocean) to Aus is probably shorter, not sure the 777 can do it due to ETOPS rules. Westbound from Aus will be this distance as the winds don't change much.
Can the 300ER go the extra distance without a payload penalty? I don't know - maybe you can enlighten us?
If ZFW is restricted, say goodbye to staff travel. EK will rather take another case of lamb chops than a pax on ID90 ticket.