Mark, you'll find differing opinions on this, but unmalted flour doesn't realize it's true potential unless it's baked in 90 seconds or less. With your powerful oven, a balanced 90 second bake might be feasible, but it's extremely advanced pizza making. I would, for now, tackle the style that is the easiest to achieve with your equipment. For the insert, that's New York– KABF or all trumps (the all trumps is bromate, correct?), a four to 5 min. bake, 3% oil, 1% sugar, and, for the best possible oven spring, an appropriately low thickness factor– no higher than .075.
Another big player in oven spring is proper fermentation. How long are you fermenting your dough for, and is it between double and triple by the time you stretch it?
Scott, I have played with cold retarded ferment for 48-72hrs, also 55-59F for 48 hrs. I do always get at least 2x rise, sometimes on the longer ferment times I have been stretching and folding after 24 hrs and reballing, gently.