In addition to Craig and Bill's advice, I would add that you need to be gentile in shaping your crust, particularly around the rim. Too much over handling will deflate a lot of the dough matrix you are trying to achieve. Also, make sure your dough has had sufficient time to double before baking, especially if you reball your dough out of the fridge.
However, if a big hole structure is what you're after, you can always attempt at Pizzarium or pizza bianca style pie. Plenty of "spider-webbing" in those pies with minimal effort due to the high water content (+75% hydration).