BNE-LAX has been 2-class frequently operated by 4-class plane in the past (maybe 1/3 of the time); but this may be changing when AKL-LAX becomes A332 as the AKL 744 used to rotate through to BNE for servicing. Obviously the A332 will either be serviced in LAX or more likely rotate Trans-Tasman. As for best upgrade chance, AKL-LAX Y to J upgrades are just about a sure thing these days (last time I flew this flight there were 1 pax per row in J, less than 20% loading -- hence the change to an A332 for this route).