Mr Angry, EK does recommend sleep/rest patterns for all ULR pairings, although they are apparently produced by people who have only ever done one from the comfort of a first class suite and therefore didn't find it the least bit tiring.
These 15 hour plus ULR pairing are horrible but what makes them worse is the other stuff they fill a roster up with as well.
The required rest after one of these epics is 2 days, and often that is all we get.