A few quick things.
I've never seen the polly-0 fresh, but I'll look for it.
Playing games with aluminum foil is the best way to adjust heat. The shiny side really reflects heat. If covering the stone with foil on the bottom is keeping the bottom too cool, try using foil strips with gaps or a sheet with holes poked in it or something. Over time you will solve this issue for sure.
Patsy's dough is not that high of a hydration. I've never worked on percentages the way you guys do, only by feel, so I can't give you numbers. Maybe I might have to get more scientific and start measuring more carefully. But I can tell you for sure that Patsy's in not a very wet dough. I've bought at least 5 doughs from them and I've even taken one to Atlanta and baked it in my oven. It's highly elastic, the most windowpaned and blistered doughs I've ever felt, by quite a margin. But it's a fairly dry dough actually. In fact until recently I was always trying to get a drier dough to match Patsy's and that's why I think I had so much trouble getting a mixer to handle it. The wetter doughs are much easier on the machine. Right now I use the DLX mixer and I love it. But now that I've gotten my dough wetter and wetter, I could probably go back to the Kitchen Aid and actually get it to work. But even as I'm adding water to my dough and improving my pizza, I'm aware that I'm actually moving away from the Patsy's drier dough. The mystery continues...
Re: Starter vs. Biga, vs Poolish: Ok, I see how you are using the terms. I use the term starter for any natural (sourdough) yeast mixture. Anything other than commercial yeast is a starter to me. Poolish is wetter, like a batter. Biga or Levain is drier, like a dough. But neither has salt or commercial yeast. Just flour, water, yeast. That's it.
I haven't tried a pizza without commerical yeast booster in a long time. But maybe now that I've got a lot of other things going right, I'm going to try it. I'm going to try the very little yeast method very soon, one with commerical yeast and one without. But I won't get to it this week.