Personally, i would only use hunters curve for non flush valve area sizing (with diversity) and consider the toilet rooms to be more like a dump load. Come half time, virtually all the flush valves are going to be in use nearly simultaneously, thus making values for Hunters very suspect in those areas.
Sloan Valve had a publication where they gave expected flow rates for stadiums based on flush valves. Its an old publication, i.e. pre low flow fixtures so you have to adjust their values, but say for a toilet room with 20 flush valves, you could be looking at 100-120 gpm, just for the toilet room.