Bob,
It would be helpful if you got every measurement (because of the tapering of the pans) of a large square Jet's cheese pizza. I would also like the weight of the baked pizza as soon as you can weigh it. I have even gone so far in the past of scraping everything off of a purchased pizza in order to get a rough baked weight of the crust only. Usually the cheese is congealed and, especially if the sauce is on the thin side, it gives off a lot of moisture during baking and leaves just a little residue on the crust. For now, there is no need for you to go that far. You should enjoy the pizza--after you have taken all of the measurements. With your measurements and Hog's measurements, we might be able to tell if the scaling of the Jet's square pizzas is proportional. It is quite common for that not to be so, either because of assembly or baking considerations or because operators like to work with dough ball weights that are not oddball numbers, like numbers with fractions. It is also possible that the dough balls used to make the small pizzas are combined to make the larger pizzas.
I would also ask for a sample of the Jet's regular pizza sauce on the side. Sometimes pizza places have those little tubs of sauce for customers to use for dipping crusts but those sauces usually are different than their regular sauces and contain preservatives that can give the sauce a medicinal taste. I usually tell the workers that it is for my daughter for dipping purposes and she won't eat the sauce with the chemicals. If you can get a sample of the sauce, I would like you to examine it for things like seeds and small pieces of tomato skin, any chunkiness of tomatoes, and anything else that you can see. It will usually be herbs, which we know are in the sauce if Jet's is using the Castella herb pouches. You should also taste the sauce to detect things like salt, sugar, pepper, garlic and herbs like oregano, which tends to be one of the most common herbs used in pizza sauces. If Jet's is using a Stanislaus tomato product, as I suspect, it will be naturally sweet because Stanislaus uses fresh-pack tomatoes that are processed during a very short window after picking, which makes the tomatoes sweeter than most brands of tomatoes.
If you can take and post some photos of the Jet's pizza you buy, for example, after slicing, that might be useful since real pizzas made by chains often look different than the pizzas shown at their websites. A crumb shot showing the height of the pizza would be especially useful as would a shot of the bottom crust showing the coloration and degree of crisping.
I would be very surprised if Jet's is using high-gluten flour for the dough for its square pizzas. If that were the case, they would only have to use one kind of flour, not two as shown in the Jet's video and also in the Barbados document. At some point, I would like to find out whether the flour used for the Jet's square pizzas is bromated or not, and also whether it is bleached, as the Northville data suggests. You might try asking a worker at the Jet's you go to if their flour for the square pizzas is bromated. Often workers don't even know what bromated flours are. I usually explain that bromated flours are outlawed in California and that a member of the family from California who will be eating the pizzas is sensitive to that.
I would hold back for now on getting supplies and pans. I'd like to get the numbers for their pizzas as best I can and then decide what is the best way to proceed from there.
BTW, where are you located, near one of the Jet's shops in Michigan or at a franchise location somewhere else out of that state?
Peter