Another seating question, I'm afraid.

I'm on a 70J 747 JFK-LHR in September and not only am I going to have to suffer the indignity of not being in 62K; 62A and 64K are taken as well.

Obviously I will keep an eye out to see if one of those frees up, or hope I can grab 64A at T-3, but failing that, where should I go? I'm 6'4" so the extra legroom is extremely useful when sleeping. I'm familiar with Swanhunter's wonderful guide and 14A, 14K and 63J are all available, as are some other UD window seats like 61K without extra legroom.

Given that I intend to sleep the whole flight, should I just choose 14K? I haven't sat downstairs on a 747 (apart from in F) for over two years and I think I would find the experience rather unnerving. I'd miss the window storage too - I need my books etc. prior to take-off. And isn't an aisle seat like 63J rather too exposed to sleep properly? But then if I opt for 61K, I'd be squashed when sleeping. Help!