Just a quick hint on the side. When you arrive at a destination, try and adapt your activity to the appropriate time of day. For example, I arrived in Singapore (6 hours ahead of SA) at 7:30am and made myself stay awake until 6pm at night.
If I had allowed my self to sleep during the day, I probably would never have slept at night and then my body clock would never have adjusted.
By going to sleep at night, I woke up the next morning at 8am – a full 14 hours sleep. I woke up feeling fantastic and managed to have a very active day without feeling tired.