Sorry that I keep adding bits and pieces of information.

Minumum stay; 14 days ( None for ex-USA)
Maximum stay: 6 months ( 1 year for ex-USA )
Unlimited Stopovers, but backtracking allowed only when for transit, i.g., @HKG.

Reservation for the first sector of the trip must be made 7 days prior. The ticketing (payment)also must be made 7 days prior to the day of departure from the point of origin. The remaining sectors may be left OPEN.

Yes, BOAC, ( luv ur name, btw ) I believe the first class fare does exist. If you can cross Pacific on CX and just do CO over the Atlantic, it might be a very comfortable deal indeed!, As for backtracking, its best to have a proposed itinerary and check with your local/overseas agent to see if computer will accept it. I think the interpretation of backtracking might vary according to the point of origin. The routing should not be as flexible as OWE, though, as this fare does not interpret the routing in terms of a movement from a continent to another. Its more of a traditional directional routing.
But, DPS is possible, for instance.