I think two hours a day is plenty.
6hours of school(maybe hour to get there and back so 7hours)
Sports?(3-4hours)
Homework(1 hour)
Now your idea of game time(8hours).
Bit much? Game shouldnt > education.
No no no listen I said some people can easily manage that. Lol, I do about 2 hours of sport a day but, it's all in school like rugby (american Football) Soccer, tennis badminton a lot, but I am just saying a little more would be better as were going to start getting a few more players online

I don't mind though.