If all the subjects aren't done every day, it is doable. I agree that it would make for too long a day for a 5th grader to do EVERY subject every day. Maybe trade off history/science, Spanish/Latin, memory work/logic? Do one 3 days a week and one 2. You could do first subject 3 days and second 2 days on even weeks and the other way around on odd weeks if you want them to get equal attention.