Dubai - 5 watches and a 10 day cycle
2 morning (0700-1400)
2 afternoon (1400-2200)
2 nights (2200-0700)
Sleep day
3 days off
The 2nd night is the killer and nights are our busiest shifts by far. There is talk that we may move to a rostering system next year. Leaves good though, 36 "working days" (doesn't include days off) which you can manipulate into at least 60 days leave per year.
Don't know of a legal 4 watch system.