abc,
I completely agree with scott r that NY street pizza operators do not use starters. What you may have in mind is the fairly common practice used by pizza operators of "recycling" leftover, or "scrap", dough that may remain unused at the end of the day, or just before making the next dough batch. Depending on the age (fermentation) of the dough, it can have flavor effects on the next batch of dough, but in most cases the recycling of the dough has an economic purpose--to save money by not throwing stuff away. In fact, if the flavor effects are too different, customers may notice and complain about the inconsistent results. There is also a practical limit as to how much of the scrap dough can be recycled. In case you did not see it, not too long ago I discussed this aspect at the Lehmann thread, at Reply 388 at
http://www.pizzamaking.com/forum/index.php/topic,576.msg25670.html#msg25670. As you will note there, it will usually be necessary to use something close to the normal amount of yeast for the next dough batch. This is because a "spent" dough is unlikely to have sufficient leavening power of its own to leaven the entire new dough batch.
I might add that there is a way of getting additional flavor in a crust by making a special batch of dough and adding it to the next batch. This is described by Tom Lehmann here:
http://www.pmq.com/cgi-bin/tt/index.cgi?noframes;read=24812. In another writing, Tom described the process, somewhat more simply, as follows (in italics):
Take about 5-pounds of dough and place it in a plastic pail and leave it out at room temperature (covered) to ferment all night. Then simply add this to your fresh/new dough that you make. This will help to boost the flavor too, something like a poor boys sourdough.I have no idea as to how common it is for pizza operators to use the approach described by Tom. However, it shouldn't be all that difficult to try once you decide what percent of the total dough weight the added "preferment" should represent.
As for the protein content of the All Trumps flour, if you go here,
http://www.gmiflour.com/gmflour/pflour.asp, and click on the number 50121 or 50111, and then the Product Specification link, you will see (in a Word document) that the All Trumps (either bleached/bromated or not) has a protein content of 14.2 +/- 0.3%. As you will see from the Pizza Glossary, at
http://www.pizzamaking.com/pizza_glossary.html#S, the protein content of the KASL is 14.2 +/- 0.2%. King Arthur is known for its tight specs and, in practice, their flours tend to be a bit higher in protein than its competitors. However, in the case of the All Trumps, one is unlikely to notice the difference in protein content.
I also wouldn't be surprised if some NY street pizza operators use a lower protein flour than All Trumps or KASL, especially if they do a delivery business. It is not uncommon for crusts using high-gluten flours to get hard and increasingly leathery by the time the pizzas reach the delivery location. Using a bread flour, which will produce a softer crust, sometimes is a better choice for delivery purposes.
Good luck with your continuing research.
Peter