I took 2 weeks off and my husband took the 9 months parental leave so now there are two of us home all day everyday. I couldnt quite do it alone with a newborn, so I like the situation we have now. 2 adults, 7 kids. (2 of our own).
I kep all my parents, as they were able to get last minute back up care for that time I was off.

If your hubby is not enjoying the idea of being your "helper" for a few months, then I would suggest you take at least 3 months off after baby is born. It would be so difficult running daycare, getting no sleep, plus your own children at home keeping you busy! ouch!
you could let your parents know once you are pregnant with an expected due date, and if the can find alternate care for a few months, fine, but maybe advertise a little later on with the expectation that you my lose some families.