Looks delicious and I made one in a normal home oven last night..

Couple of questions from me..
Oh.. are we not supposed to use a roller to flatten the dough but rather hand stretch it?
Also, what is the semolina flour for? Is it to allow the dough to be more easily stretched without breaking? And I assume that would produce a chewier dough as well?
Have your tried any sourdough pizza recipes?
Any tips on oven temperature and cooking times?