Baze .. I am a United 1P and have pre-booked 8B on a 3 class 777-200 from SEA-DEN next trip. I think that is a bulkhead. It is a Business class seat, but still the same story.
The EXIT rows (30) I flew UA 777 in coach to Buenos Aires in Jan .. great room there and is my suggestion, and any 1P can pre-book as you said.
Exit rows in 777 are great for couples travelling together, as unlike with 747 which is 3 abreast, where you gotta hope the alleged "Premier zone" is kept for you (it never is on 747s!) the 777 is a dream run IMHO.
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~ Glen ~