out of curiosity why do you say a 4 day pattern is inhumane? Jetlag? Almost every airline in the world operates to destinations short and long haul with only a 24 hour stay, Emirates being the prime example! Also I could be mistaken but don’t the pilots at CX always only stay everywhere 24 hours? If they do it then it must be legal and safe, I believe the theory is that the less time spent away from ones home base the less likely it is one will suffer jet lag and the quicker you can return to base and recover!