just the two guys in the seat being rested for takeoff and landing (which is how many of our crew interpret in-flight rest requirements).
That is exactly how I interpret the requirement both as heavy or operating crew.
The first airline in which I flew heavy crew would as standard have operating crew fly (roughly) first six hours, heavy crew next six and operating crew back in half an hour before ToD.
How it's done on the day is up to the operating captain - you'll all get there one day
