As someone who has run shows with that many bands, you better have:
1. A big hand clock or digital clock visible from stage.
2. Iron fisted stage manager who will cut a band when their time is up.
3. Shared drums and cabs. Not sharing adds 10 minutes to the set changes and makes the first song a soundcheck/drum tweak.
4. Get a listing of what everyone needs in their monitors to set that up from the start, this includes lineup (# guitars, singers, keys, acoustic, etc) and who needs what in the wedges where.
5. A good tip for the sound guy, that is going to be hell.
Been there, done that on time.
