How many Wireless Clients on RB951Ui-2HnD

We have a site with over 300 wireless users and due to frequencies 3 APs. Currently we have 3xPicoStation M2 but they have intermittent issues, probably from being overloaded.

How many concurrent wireless connections can the RB951Ui-2HnD handle?

What’s the best way to add more APs close together without frequencies overlapping.

Thanks in advance.

Hi,
i think about 80 or 90 clients,
WDS is a good scenario