I need to create a 24x7x365 work schedule for an aircraft maintenance program. Here are the parameters:

1. Each FTE personnel can work 1800 hours per year before overtime kicks in
2. Saturday and Sunday need a minimum of 3 personnel working at a time. keep the count to as close to 3 for those times as possible. 
3. Approximately 75% of the manpower is needed between the hours of 0730am and 10pm Monday through Friday 
4. 20 FTE total 
5. Only 3 FTE are needed between the hours of 10PM and 0730am 
6. Personnel can work a maximum of 12 hours in on a single shift 
7. Try to avoid overtime. overtime is considered more than 40 hours in a week. If overtime is required, make sure to identify it.
8. No part time personnel. All FTE must work full time even if it increases the overall FTE count to above 20; however, keep it as close to 20 as possible. 
9. Personnel need to have at least two days in a row every 7 days. 