what is your point of schooling? To learn something right? Then if you have a controlled schooling or least controlled to the best of your ability then you allow school to go as long as they are learning and still showing eagerness. You should also be learning about your dog, have they adapted to the different styles they faced or are they hard headed and refuse to change. How do they respond when they are on top, how do they respond when on bottom versus whatever style.. It's not a timing thing, some hounds can do in 3 minutes what others cant in 30 mins. It's about learning what you can about your hound while they are also learning different things. Some things you cant put a time on.