AA;
This is how we do it:
Pilots flying the takeoff do the landing.
If the Capt flies over the FO sitting in the right seat for TO and LDG is the IRO on the homeward leg.
If FO is flying over he is IRO on the way back. Of course the capt occupies the Left seat at all times
Pilot doing the TO and LDG gets the break of their choice. (Most take mid)
IRO normally gets first break
PM normally gets last break.
Pilots are required to be up front one hr prior to touchdown
No pilot should be in a command seat for more than four hours before landing.
FOr ULH they can split the flight in half or do a Long, Long, Short, Short sequence for breaks. It is up to the crew. In reality the three man ops can do what they want to but the way I described is the preferred method. We do have crews that let one pilot do the takeoff and one the landing, and capt always takes mid break.