This is a post from when I first joined and did not get these questions. Now that I have found them I will answer. I hope you are told by the forum of my reply.
Just because you see it in a New York Pizzeria don't make it right. The tools of the trade are unique and all though anything can be made to work does not mean that is the way it was made to work.
Look at the shape of the pizza peel its function is even in its name. It has a basic square shape with sharply rounded corners. Usually the blade is smaller then then the pizza board used to make the pizza. The peel may have a 12 to 14 inch blade and the pizza board is 16 to 18 inches in a strong round finish at the leading edge and the peel with a straight section between the corners.
Back in the day Blodgett, Bakers Pride, Wolf and most makers of pizza ovens did not use slabs for oven deck but rather 12 x 12 inch blocks or tiles were used to create the oven deck. That meant that the soft thin dough covered with sauce and cheese would ease down into the small cracks and spaces where each brick met. Therefore the oven tender will use his tool the peel to come in from the side of the pizza with the corner of the tool and twist the handle to lift the fresh setting crust up from between the cracks while in a quick scoot moving under the pizza freeing it from the first sear that set the dough to spin the pizza so it will cook evenly. About a 180 degree turn.
The board is used to build on and place the pie in the oven. It is wood for a reason. It helps extract some of the dough moisture and you can use flour to put in the oven. This becomes important over the course of a shift but has little to do with making one or two. The cornmeal used by some creates its own smoke and flavor from the oven. Toasted or burnt corn works well in a southwestern flavor profile but just ain't for pizza. When used in a shop the smell of burnt cornmeal will saturate an oven and foul the pizza.
Remember to flour buff and scrape the grain and fiber from your board or you will have less success then you want.
Now let me say I have worked in more then one shop along the way where the shop owner was to cheap to buy or replace the wooden pizza boards and used and trained new pizza makers on the large pizza peels with cornmeal. The new guy just thinks that is the way it is done so given time it get propagated via familiarity in the do as Joe does training methods. Even if it becomes common it does not make it right.
So there are the tools and who they are meant to be used. What other people do is their own business but I suspect that you will find it worth the money to get a board if you want pro results. Also a screen is always a compromise to quality
You may want to seehttp://www.pizzamaking.com/forum/index.php/topic,1367.0.html