I'm planning a trip to Japan from Dubai and want to use my points to upgrade from economy to business. Is there a way to check how likely it is there will be seats available, often after I have booked in the past I find there are no upgrades available. I thought maybe there is some way to check beforehand or do I call Emirates before booking?

Is there a general consensus on which is the better business class on Emirates, the 777 or the A380 - both types fly to Japan.