FoxtrotAlpha18.
Do you know what you are talking about ?
The B777-200LRF can carry over 100 tonnes
of payload over the range you mentioned.
This is almost a B747-400F payload.
If the EK aircraft are fitted with the optional
fuel tanks as on the passenger versions the
SYD-JFK sector will not be a problem if the
payload is 'light'.
The B777-200LR endurance is over 20 hours
with a 'light' payload if the optional tanks
are fitted.