787 - 9 abreast = 16.9 inch wide seats
747 - 10 abreast - 17.5 inch wide seats
A380 - 10 abreast 18.5 inch wide seats

They speak for themselves 9 abreast 787 will be narrow - i have to say having flwon EK A380 recently Y 32 inch pitch i thought it was a very comfy aircraft for Y - knees no where near the seat in front and im 6'3