It depends on the skills of every player . Personally I will play one , two at the most with focus and concetration , the on eof them the most important , the other less . more than two I start making (more ) mistakes , but then again play only one game is boring generally, dedicating so many hours just for one game if I had better knowledge of the game i would love to multitabling many tables , that would be fun and would keep me interested in the session all the hours .