Except in profitability, which is a key separator.

I'd expect WS to make a move soon if they're planning on ordering 787s. Even with a strong Boeing relationship, there aren't many slots available for the 787, or A350. Which makes me think that maybe A330s will be leased in the meantime if / while waiting for 787 deliveries. 767s may be an option as well, but many on the used market will be older with more cycles, and may not fit as well with WS' cargo ops.