Mary Ann, if I understand correctly, you intend to use the stoneware pie plate to allow the dough to proof (after final shaping), and then to bake the dough in. Also, you intend to use parchment paper.
My thoughts: if using a cold, room temp pie plate, you won't get the same open crumb - in fact, you may be rather dissapointed with the end result, considering that it would take several precious minutes for the stoneware pie plate to heat up, and during this time a crust will be forming, impeding dough expanion. Ideally, you'd want to place the dough directly on a hot pizza stone, slash, then cover with a tall all stainless steel or aluminum pot (which has been preheated also).
If you want to score the dough before going into the oven, that should't be a problem at all, just make sure and score it immediately prior.
Regarding the use of parchment paper, how exactly do you plan on using it? I've never used it. Despite the high hydration, if you do enough stretch and folds, the dough will maintain a ballish shape.
I think if you allow the doughball, after final shaping, to rest, seamside up inside of a lined lined bowl (you could use a cotton dish towel, or something similar - make sure and sprinkle it generously with semolina flour prior to placing the dough), you wouldnt't need parchment paper at all. Once the dough looks suffiicently risen and feels gassy and alive to the tough, simply plop it out onto the preheated pizza stone.