Not strictly related to 767 lifestyle but screw that!!! If I were you I'd take the 747 position, do 5 years of seeing the world and when your freeze is up after 5 years you can move back to shorthaul with some seniority if you want to. The 767 is a dying fleet and there's every chance in two years time when the 787s arrive you could find yourself directed off the fleet (ie another conversion course!) on to the 747 or 777 or A320 anyway.