Single foster parents - How many kids?

I am a single mom with a more traditional work schedule, typically 9-5. But work in home health so can re-arrange my schedule as needed to accommodate appointments. Much more flexibility. I am pretty comfortable with 2 right now, but it is REALLY nice that they are both old enough to dress themselves, toilet themselves and play on their own with only minor supervision. I think I would be more stressed with younger ones. It also depends on other factors: Age of the kids, Health of the kids, personality traits (high strung, temper, easy going etc), visit schedule with birth parents and and appts that need to be followed. I would be stressed with a kid that needed weekly PT/OT/ST or other things. My 11 year old gets counseling 2x a month, and that is even rough with work, homework from school and bedtime routine etc. You kinda have to learn to have a schedule, but tolerate a more "go with the flow" attitude at times. Otherwise the ups and downs will drive you crazy. I could probably handle 2-3 at a time max. Plus, only can carry 3 littles in my car at a time, and won't take kids old enough to sit in the front really anyway.