A master switch and a contactor to turn all the lights on at once may
not be the way to go......at least not in Sacramento, California (where the OP is from).
Individual switches abound because of Part 6, Title 24 (CA's Energy Code). Care must be taken for separate switches to take advantage of daylight areas through windows and skylights, divide everything into 5000 sq ft areas for the purpose of bypassing the required 7-day-programmable-timer for a maximum of 2 hrs...............the list goes on and on.
Lighting controls can become quite complicated in no time at all.
If anything, I'd suggest installing individual switches for each circuit breaker that powers lighting. This will keep the manager/clerks/hired-help out of the panel (I wonder how many times a week they shut off the cash registers or computers mistakenly
)
