Korean Air Skypass - Best J seat on KE 744

Any KE regulars able to advise on which seats to choose (or avoid) on KE 744 LHR-ICN route?
I am leaning towards upper deck as other half has not flown 747 upper deck before.

Your flight KE907/908 will be flown by 74B version (335 seats).

I am leaning towards upper deck as other half has not flown 747 upper deck before.Just hope that they don't oversell Y and use the upper deck as overflow. Yes, I'm bitter. :mad:
http://www.flyertalk.com/forum/korean-air-skypass/991918-744-upper-deck-economy-passengers.html

I don't like the seats that much at all for a few reasons. Rock hard padding and armrests at different heights are the two main ones. Beyond that, row 10 on the port side was a bit loud due to the galley so I'd skip it. On the plus side, it does have a bit of extra legroom, I think.

Well flight appears to be booked solid going by seatcounter and ITA. Only First seats still available. Hoping that does not mean that upper deck turns into the overflow cabin.

Is there any advantages for seats on the lower deck?