Check out http://www.routehappy.com. It tells you what flights over your route are most comfortable. On twitter it is @routehappy. On my flight to ATH from JFK, a DL 763 flight with true lie flat seating got a score of 8.9 compared to a flat at an angle flight rated 7.9. An angled seat in an A330-300 coming out of FCO got an 8.1 as the seats are wider and more comfortable. It was a fun site. It could not do ATH-SDF on my flights unless I did each leg separately.