I'd go with most convenient airport first and if everything else is equal I would take the 767.
On a side note...
It seems most people want to be in the upper deck of the 747 but want no part of a 757 on a short TATL flight. I just don't understand that. The upper deck of the 747 is equivalent to flying on a single-aisle aircraft. If you like the upper deck of the 747 then a 757 should be no problem.