All the data I have goes in favor of the 777 vs the 744 in terms of FF compared with weight.
Fuel planning data (x1000 lbs);
777 landing weight 400 lbs
744 landing weight 500 lbs
...............777......744
4000 nm....118....174
3000 nm......87....127
Also BADA data and long range cruise tables show a similar picture.
How this compares
pr SEAT however, I have no clue...
Cheers,
M