It is correct that SYD
was always in the plan. The 744 carries 100 more pax than the A346, so they are not competing aircraft. The A346 however does carry a lot of freight and that is what they needed more of in Sydney.
I obviously don't have data for the 777-300ER. However for the 773 in our configuration, MTOW is 263tonnes. Our data for Engine INOP max alt shows at 300 tonnes up to ISA+10 we can maintain FL140. We don't use full TO
rating at the moment, but if we did, I believe our MTOW would be around 300tonnes, or certainly towards it. At these weights we cannot clear some of the highest terrain on our European routes. We would definately use different routes, namely the more northern routes over Mongolia rather than the route south of that over Urumqi. Air France currently flies 772s HKG
, but not sure which way they go, north or south.