I have a long (13hr) flight coming up in less than two weeks. Right now my wife and I are booked for an aisle & window on a 3x3x3 flight configuration (787-10 Dreamliner) in rear of place.
We have middle seat between us open. Right now there is still abut 20% of seats in the rear open. (There are 8 sections of 3 seats in a row that are wide open)
We are have two options.
We can stay put and try to sleep in some fashion using the middle seat as space. OR....

We could pay $34 each and move to preferred seats. Right now there are 12 of 18 sections of 3 seats wide open. So if we move we get middle of the plane but also we could each book a middle seat in a 3 seat row and HOPE that get the full row.
What are peoples thoughts on this? What is best way to get chance of being able to sleep on plane.