Steve87 wrote: I will probably book the larger chairs on the plane with a little extra to have more comfort.
If possible consider getting a "lie flat" seat on your return flight. The seat goes completely flat and 6' long so it's actually very comfortable and easy to sleep. I had that on my 3 hour return flight and slept the entire time. I think Business Class usually has this option. Credit to @Tangerine for this great suggestion.