The thought of 10 hours in a middle seat leaves me cold.
I have flown in a 767 to europe, but it was AC Rouge, which is the equivalent of traveling by rail in a coal wagon.
My ideal would be A330 or even better A220 but they are scarcer than hen's teeth.
I did a connecting leg from Toronto to YVR on an AC 777. It was continuing on to OZ. I felt sorry for the poor souls jammed in there for another 12 hours.