grow room specs

Hi i am helping a mate do a new room the specs are 3.65 metres long and wide along with 8 foor high.
My question since he is running 600watt hps how many lights would do for a room this size thanks.

Roughly 1 600w per 1m or 1.2m squared.

As many as possible without overheating or overloading anyting. Realistically, Kush is right.