Building a Staffing Schedule

Build a staffing schedule for the following scenario:
GI Outpatient Lab
2 procedure rooms
4 pre/post bays
1 front desk
Approximately 12 cases completed/day
Hours: First case begins at 6:30 a.m., but patients are asked to present at 6:00 a.m., the last case is scheduled to begin at 3:30 p.m. Need staff coverage from 6 a.m. – 5 p.m.
Staffing: You need 1 nurse in pre, 1 nurse in post, 1 nurse in each procedure room, 1 tech in each procedure room, 1 registrar, 1 MA and 1 nurse to help do phone calls, scheduling, etc...
You have:
(7) nurses
4 nurses work 4-10's
2 nurses work 3-12's
1 nurse works 5-8's
(4) techs -5 day/week 8-hour shifts
(2) registrars - 4 days/week 10-hour shifts
Lunch break – 30 minutes
Do you have enough staff to cover the shifts needed? If not, what do you need? Do you have too many?
Based on what you decide you need in terms of staff, build the staff schedule for one week, Monday - Friday, based on the assumptions above.
What was the most challenging part of building the schedule?