Don't. Just don't. Seatguru is horrible nowadays ime. Regardless of airline, it adds no value for me.

I guess 64A or K are the most sought after seats on the 747. However, you'll have a hard time getting either of those unless you have status.

Upper deck on the 747 is usually a bit more quiet than downstairs, so I prefer it. There is also something magical about walking up the stairs on an aircraft.