At 6"5" I am not sure my recommendations will help you. I have sat in row 20 and row 31. Pitch appeared to be the same in both rows, and maybe I got the 33" - it was a nice seat and both flights were good. I sat in the A seat which has no underseat equipment.
I did find I preferred the front Y compartment where row 20 was (rows 15-thru-27) over 31 due to aisle traffic. I noticed more coming and going at row 31, and the front compartment was quieter. If you still have a choice, pick a row between 16 and 26. Row 15 is exit/preferred and 27 does not recline. There are no missing or misaligned windows after row 16.
Front compartment also helps you get off the plane quicker to get in line for customs and immigration and bag claim. Every little bit helps after a long flight......
Hopefully your flight will be smooth so you can get up and stretch a bit from time-to-time, because if the seat belt sign is on, DL
is good about announcements to return to your seat. We still had a knucklehead or two who were up and about during turbluence, but announcements were made firmly to remain seated or return to "your seats now."
I really liked the AVOD and overall feel and appearance of the 764. Nice airplane.
Good Luck with your ride,
watch what you want. you may get it.