Opening hours do not influence overcrowding. Overcrowding starts at the door and can only be solved there.
One easy way would be the ban of pre-purchased tickets.
Visitors are as greedy as club owners. You paid €50 for your ticket you go in no matter what happens. And the club owners off course take everything they can.
1st, If you can only pay at the door it is much easier to overlook the number of sold tickets. If the maximum capacity is reached, no further tickest will be sold unless someone leaves. Same system like in a parking garage.
2nd, As soon as people see the 200m long queue at the door, some turn around an leave.
3rd, To avoid the queues at peak times peolpe will come erly, which means they are wasted more earlier and leave therefore earlier. Reduced contact with schoolkids or workers in early morning public transportation.