info request: devices to control or mitigate effects of queuing.

Employer wants to achieve "no-wait state" for restrooms adjacent to factory
cafeteria serving 2000+ per day. What are some ways to calculate numerical
requirements/time for a given population? What devices may be used to
distribute usage when numerical requirements cannot be practically met?
Any pertinent experience or literature references would be useful.

Thank you, Robert Davis, Architect
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