Originally Posted by RickyT

Apart from fuel-consumption, one other factor that CX may choose to operate the 343 is that the markets they serve (eg AKL, DME, FCO and to a certain extent JNB) has insufficient demand to sustain a F cabin and a large J cabin (53 or 57 on the 77W compared to 26 on the 343).

What I think CX may do (and this is pure speculation) is to configure some 77W in J/Y+/Y. Not only would this resolve the need to use those thirsty 343, it would also suit the nature of the routes the 343 serves.