How many children do you have? We home schooled with"Seton". We did fine. Year round schooling is best.
Whatever your children respond best to, is the bottom line, but we take a summer break, usually part of July, and all of August and September, nine to ten weeks in all. I'm of the philosophy that children and teens need that summer off, back in my day, summer vacation was basically Memorial Day to Labor Day, but the educational establishment has gradually whittled away at that, making vacation from early in June to mid-August. We basically follow the older pattern, but bumped up a month, both for climate reasons (Southeastern US) and because vacation hotel rates go down after the first of September.