Interesting. EK 772LRs have 266 seats in a 3 class config and that's with 10 across in Y class. Its the only aircraft in the fleet to make less money than the 345 as it has only 8 first class seats in stead of of the 345s 12 (258 seats total on the 345).
Would be a bit of a squeeze with 300 on board wouldn't it?
The Don