system
A chat on subreddit /r/me_irl
human
Actually most pizza places do use fixed measurements for sauce, cheese, and toppings.  If the dough is for 15" then all the toppings would be for a 15" pizza.  If it's less stretched out the toppings will just be closer.
gpt
No they don't. They have portion sizes they're *supposed* to follow. But it's typically just eyeballed.