The issue with Calcutta is the amount of units Davvyk has stacked there. I can't even bring enough to match him, let along have a solid chance of winning, even if I manage a surround. And that leaves nothing for other attacks like the Dutch or Philippines.
As well, if I attack Sydeny, I can remove both a bunch of Allied units and a VP mostly permanently, with the US fleet looking to be going towards Europe
The argument about not going to Sydney is your fleet is out of position for at least 2 turns. I would not go to Sydney and go for Calcutta.
The issue with Calcutta is the amount of units Davvyk has stacked there. I can't even bring enough to match him, let along have a solid chance of winning, even if I manage a surround. And that leaves nothing for other attacks like the Dutch or Philippines.
As well, if I attack Sydeny, I can remove both a bunch of Allied units and a VP mostly permanently, with the US fleet looking to be going towards Europe