Typically a rental stage of that size would have 400-600 amps. This is because the legacy lighting kits are tungsten units that come in sizes like 10K, 5K, 2K and 1K watts.
Nowadays with fluorescent and LED lighting the power budget can be much lower, so ultimately it depends on what and how many units you intend to you.
Best practice would be to design your lighting plot for you typical application, add some extra, know that you don't want to exceed using an 80% load and go from there.
Practically, you must decide if you ever want to use a 10K or a 5K lighting instrument, and if so, you'll need the proper power distribution equipment in addition to the power supply. Most stages provide CamLock connectors that feed "Distro Boxes" with 100A and 60A Bates Connectors that feed 100/50A "Lunch Boxes" with household connectors.
The small (under 20A units) connect to the Lunch Boxes and the bigger units to the Distro Box with 100/60A Bates extension cables.
As you intend to be hiring lighting crews, you should consider to hire a Lighting Director and or Gaffer to assist you with these planning requirements. It will save a lot of headaches and expense later.