Book early or book late...

You've missed any availability that may have opened up at close to a year out...but more availability may open up between now and then...and most likely in the week before the flight (or even the day before).

But it's a gamble waiting until then for tickets, as WTP may be sold out by then or others with WTP may also be playing the waiting game.

And it might be that no availability opens up at all.

Other option is to do a cash upgrade - either when booking if available, at check-in or at the airport. Also a gamble as to whether it would be available or not.

It's the fixed dates thing that makes it tricky, that and not booking as soon as space is released...