One of the issues is the overlap. People who need day shift won't be leaving till 4-6 pm and people needing evening shift would need care starting at 2 till midnight. Those wanting third shift would need care to start between 10-11 and not be available for pick up till 7-8 am.

If you are interested in doing the longer shifts what you could offer is care for those doing 12-14 hour shifts such as nurses. Generally they work 7am - 7pm needing care from 6 am till 8 pm. This would provide a valuable service but still allow you to have a full night's sleep. As far as fee goes they generally only work about 3 days a week but are working teh equivalent of a full week of hours so each day would be about 1 1/2 times the regular rate considering you will be feeding 2 maybe all 3 meals.