You pizzas look great! Is the crumb shot caputo or bread flour?
I have recently wondered about the Varasano method in regards to cold fermentation, salt levels, and "windowpaning". The process goes against some convention, but the recipe seems to work well enough to open a restaurant on. You might get more oven spring if you lower the salt to 2.5% or so. And if you do a room temp ferment with 9% starter, you may well get 18 hours out of it for some excellent flavor without the cold ferment. Varasano's sourdough, which is Patsy's I believe, may well stand up to 3.5% salt, but my starters would balk (as well as my taste buds!). And if you are developing the dough to "windowpane" as he suggests on his site, you may be over developing the dough. Just my take - like I said, he has taken the leap to serving the public with his recipe with very favorable results.