Peter, that is a pizza to be proud of. Well done.
Since you're already using Mike as your inspiration, I would follow his later lead and go with some sugar, maybe 1%, possibly even 2.
Are you using the dough calculating tool to get a thickness factor, and, if so, where are you at?
Unless you're at 4 minutes with the undercrust and could push it one more minute, it's time for a better stone. 580 might be high enough to use a high alumina cordierite stone like Mike uses- maybe. Or there's 1/2" steel.
Btw, splitting up the bottom and top bake is counterproductive. Pizza needs intense heat from above and below at the same time so that when the bottom heat puffs the crust up, the top heat sets it as close as possible to it's apex. Pre-heat your stone on an upper shelf, close to the broiler, and turn on the broiler a couple minutes into the bake.