I char the bottom a bit more than desired and my lower element is turned down to 300, pretty much off once the oven is warm. I lower the upper element with 75 or 100C and raise it before launching. I wonder if this is making it too hot, or that I wait too long before launching. There are three inportant factors imo. The ambient temperature, the stone temperature and the radiant heat from the upper element. Since the upper element plays a big role, the timing relative to when the upper element is engaged is important.
One can probably achieve good results with different methods as long as the method is balanced between the relationship of ambient temperature, stone temperature and upper element time.