8 looks just about the right number for me
However, give or take 2 or 3 games or so depending on how many team games or if some games are played almost real time like (quick turn around between turns).
For example, the more team games, the lower is the gameload for me or I just lose focus. For example, Handling 8 team games at the same time is beyond me but 8 POLYs is fine. I also feel my team game limit is just 2 realistically or 3 but that will be a stretch. Anyone else feels the same way?
Hope that helps