I did the basic design for all of the dough calculating tools so I can tell you that the volume to weight conversions for the various dough calculating tools, including the one at http://www.pizzamaking.com/expanded-calculator.html
that I used to come up with the formulation you requested, came from several places: from actual measurements that Steve (the owner of the forum) conducted, from ingredient labels, from Nutrition Facts labels, and from the NutritionData.Self website at http://nutritiondata.self.com/
. The data at the NutritionDataSelf data is mainly from the USDA database. In some cases, as where there were several brands of a given ingredient, such as vital wheat gluten, I averaged the conversion data for the multiple brands. Also, in a few cases where I could not find any conversion data or a means to calculate same for a given ingredient that I had in my pantry, I conducted my own weighings.
It is important to keep in mind that there are a variety of other factors that can affect weights of ingredients, such as aging, humidity, exposure to moisture, oxidation, storage conditions, and compaction. Even the measuring cups and spoons can produce weight variations inasmuch as their shapes can vary and they can be made of different materials, such as plastic or metal, and can be subject to different manufacturing tolerances. Finally, people do not measure out volumes the same way. Some use heaping teaspoons or scant teaspoons rather than level teaspoons on which most conversions are based. I have conducted hundreds of weighings on my scales, using different measuring cups and measuring spoons, and of metal and plastic, and when the numbers are averaged, they can vary more than one might expect.
In most cases, the conversion data go out to about 5-8 decimal places. However, the outputs of the dough calculating tools are two decimal places. There are no conversions of weight to volume for flour, water or cake yeast.
My practice when using the different dough calculating tools is to weigh the flour and water and any other ingredient using in a fairly large quantity, such as the oil in the PJ clone dough formulations, on my scales. For the rest of the ingredients, I generally use the volume measurements. I even have a special set of mini-measuring spoons to use for very small volumes. That set is like the one shown at http://www.pizzamaking.com/forum/index.php/topic,5583.msg47264.html#msg47264
I am surprised that you did not get two dough balls of the specified weight. The dough formulation I gave you included a bowl residue compensation of 1.5%. That is my standard number for a PJ clone dough (and many other types as well). When I use that value, I generally have a little bit of dough left over after scaling the dough on my scale.
As for your problem with the bottom crust burning, I did not have that problem in my electric home oven with the pizza on the screen being placed on the lowest oven rack position. Ovens can vary quite widely so maybe you need to use a higher oven rack position. I do not have a convection feature on my oven but I know that some member who do have that feature say that it helps improve top crust browning. All crust browning adds flavor to a crust so use of the convection feature may help you out in that regard.
You might also take a look at Reply 45 at http://www.pizzamaking.com/forum/index.php?topic=2223.msg20965#msg20965
where I discussed several ways that I and other members have used with their ovens to achieve desired results. That post is with respect to a NY style of pizza but some of the principles might apply to an American style of pizza such as the PJ pizza with a lot of sugar in the dough.