When making pizza in an oven, the temp that has always been suggested to me was "as hot as it will go." Commercial operations often go 800F, sometimes over 1000F, but you can also cook small pizzas in cast iron over an open campfire, so there's plenty of range. If using the cast iron like a pizza stone, I'd suggest letting it pre-heat. Definitely be careful when putting the pizza in and taking it out!
Also, tangent for another time, if I have room in the smoker (usually when smoking brats or other small stuff), I will sometimes smoke some AP flour and use that later in making the pizza dough!