For what it's worth, was part of a datacenter operations department that had a 24x7 team. 4 shifts, 4 staff on each shift (1 was supervisor who did same work as the rest, 1 'point of contact' who stayed in the office). 4 days on, 4 days off, 12 hour shifts, 8-8. Shift teams would alternate between day and night (so 4 day, 4 off, 4 night, 4 off, repeat ad infinitum). During the day that was bolstered by 6 day-staff, Monday to Friday, who would have a staggered start through the day (IIRC 2 start at 8, 2 at 9, 2 at 11)
And also for what it's worth, my understanding of body circadian rhythm research suggests that "every 8 days" is *WAY* too short a period to be flipping people's shifts from day to night; every 6 months is more reasonable. Cheers, -- jra