For parents wondering what the right amount is, the right amount is simply how many hours your children wants to sleep. People on a schedule just don't oversleep. The research only really matters if you have medical concerns about your child, for example, you can't get them on any schedule, they're sleepy when they seem to be getting enough sleep, or there's some other issue.

Make your schedule malleable for your kids and within a few days you'll pretty much know exactly how much sleep they need.