We use to do a show on the beach every labor day weekend.
It was fun, anywhere between 6 to 10 bands and keep going till the sun went down.
Never had to many problems, we just start the generator and let it warm up a bit. Then wait for the RPM to stay steady. Then turn things on.
If your slick about it and add gas while its running, yah can keep going.
Otherwise same thing, turn everything off when you have to restart the generator after a refill. Instead off wasting time telling everyone to turn off, just yank the extension cords at the generator. Get the engine steady and then replug. Saves time and keeps the risk of surging peoples stuff.
We got away with a 1000 watt generator, you might get away with less. you need big power with large PA system or bands that run multiple hi wattage tube amps.
heck you can get a stinky little
2cycle generator at Harbor Freight.
But i really liked the 1800 to 2200watt four stroke generators, colemans are cheap and loud, and Hondas are really quite and expensive.