Great questions.
With one stone, I always put it on the bottom rack. But the middle would work out just as well.
There is alos a school of thought that says you should use two stones, one on the bottom and one on the top.
As far as how much dough you should use, that is amtter of taste. For my dough recipe, I get 3 or 4 very thin pizzas.
If I want a thicker crust, I cut the dough in half. And I get 2 pizzas.
Here are some pizza stone cleaning tips:
I always let my stone cool down before cleaning it. For every day cleaning, I just wipe the stone, with a slightly damp cloth. This will remove all of the corn meal or flour that has stuck to the stone. If I have something baked on the stone, like cheese or a piece of dough, I will gently scrape all the residue I can get off the stone with a spatula.
If I am unable to get it clean, I will heat the stone in the oven for at 500 degrees for an hour or more, let the stone cool and then try again to gently scrape the stone. Heating up the stone will burn off anything that has stuck to it. Then just wipe down with a cloth.
If you are interested in getting a pizza stone, please check out this page:
http://pizzatherapy.com/tools.htmI wish you well in all of your pizza adventures.
Please let us know how you make out.
albert