A 4 day, 40 hour workweek works suprisingly well for international teams, because the longer days usually mean more timezone crossover.
It worked well on the management side of things too, but with an actual "changeover", as you'd have a Monday-Thursday supervisor and another Thursday-Sunday supervisor, with one day a week of overlap however that Sunday-Monday changeover didn't have an overlap (although there was a lot of OT on this job so it did frequently happen).