This mixer is incredible.
More accurately, any stand mixer beats the heck out using a hand mixer (as I'd been doing). Great to see the spiral whipping the dough around, side to side. Dough had that supple coherence, the kind I'd seen in NY pizza places where the pizzaiolas slap it around, twirl it in the air and lay it on the paddle perfectly round. (Mine weren't THAT good, but I felt as though I'd made a quantum leap in production technique.)
My only thought was that the autolyse period (10-15 minutes rest after mixing just flour, water) didn't seem to make as big a difference as with the hand mixer. In fact, I think I got a better result from dough mixed all together & prepared later the same day (i.e. without overnight refrigeration, as with first batch where I did autolyse & stored overnight for cold fermentation.)
Will keep experimenting but so far, so good.