No.
Total H2O capacity is 2000kgs.
Typical load across the Pacific would be 1600-1800.
Have at worst case 1800kgs run down the back - same as
10 people on each deck going for a wander down the back at the same time.
The size of the horizontal stabiliser is as large as an A320 - I'm hard pressed
To think of a scenario that you would run out of trim authority!
.