I realize that you posted on the Sicilian board but the reason I asked you whether you parbaked the crust is because I have problems baking pizzas in my standard builder's grade electric oven with its baking temperature range of about 500-525 degrees F whenever the hydration gets to around 65%, based on a high protein flour. In fact, in some cases, I have elected to use a sheet of parchment paper to prevent the pizza from sticking to a peel. But either way, in my oven, it is hard to get a highly hydrated dough to achieve a good oven spring. It is like trying to raise a very wet dish sponge. Using a cutter pan or something similar avoids potential sticking problems associated with the use of a peel but the downside is that the pan has to get up to temperature before the pizza can bake. This slow and gradual heating of the pan will often minimize the oven spring. Also, in your case, you are using a fair amount of dough (based on a thickness factor of 0.138) which, together with sauce, cheese and toppings, is further likely to result in reduced oven spring at home oven bake temperatures simply because of the increased mass and the need for a long bake time to cook everything so that you don't end up with pasty or undercooked dough. And if you bake the pizza for too a long time to be sure that everything is fully cooked, the crust can end up on the dry and dense side, although the use of oil in the dough at 4% will mitigate against that to a small degree.
A while back, the above subject came up in a thread by member sub where the use of a very high hydration was discussed, starting with Reply 5 at http://www.pizzamaking.com/forum/index.php?topic=23668.msg240378#msg240378
. As you can see from the posts that ensued, it turned out that the skin was parbaked with just sauce, for about 9 minutes, with the toppings being added later. This was in the context of an oven temperature of 250 degrees C, or 482 degrees F.
Ideally, the best oven spring seems to come from using very high oven temperatures, much like exists with very high oven temperatures that are used to bake Neapolitan style pizzas, where there is a big burst of energy that hits the unbaked pizza as soon as it hits the oven. Sometimes I will see photos of pizzas that have exceptional oven spring and a nice open and airy crumb and a lightness to the crust and wonder how that was achieved. Often the answer was that the ovens used could deliver an awful lot of heat, usually considerably more than the heat that my oven can deliver. An example of this can be seen in the outstanding pizzas that Johnny the Gent makes using high hydration values, with a good example being shown at Reply 122 at http://www.pizzamaking.com/forum/index.php?topic=27294.msg304639#msg304639
. From what Johnny has previously reported, he uses a soapstone stone and an oven that can deliver a temperature of around 300 degrees F (572 degrees F) although he suspects that his oven may run hotter than that (see Reply 17 at http://www.pizzamaking.com/forum/index.php?topic=27294.msg282326#msg282326
I guess what all of my discussion is leading to is that if you would like to continue using a high hydration dough with your standard home oven, you might consider prebaking the crust since sub's work seems to suggest that you can achieve a nice open and airy and tender crust and crumb at home oven temperatures if the skin is prebaked. You would perhaps even do better if you didn't use a pan but I realize that you are making a Sicilian-style pizza that calls for use of a pan of some sort.