Wet and thin parts in pizza dough
I've benefited greatly from reading various posts on this forum, so I hope someone can give me a couple of advice on my pizza dough handling :)
Basically, I've followed this awesome recipe posted in the Pizza Primer by floydm (http://www.thefreshloaf.com/recipes/pizza), but I replace roughly half of the flour with pizza flour instead. The problem I usually encounter, is that my dough develops thin, wet spots when I try to gently stretch it into shape. I don't always see these wet spots before I start putting on the topping, so when I try to slide the pizza off the peel and onto the baking stone, the dough more often than not sticks to the peel, and I've got a roadkill on my hands...
Now, I was wondering if these thin, wet spots occur because the dough has not been kneaded enough? I've followed the instructions in the primer quite accurately, but this tearing that I encounter perhaps suggests that I should knead it even more? I'm using a pretty standard Kenwood kitchen machine with a dough hook for my mixing duties.
Thanks in advance for any thoughts or suggestions :)
PS: I just watched a youtube video of Alton Brown making pizza dough, and he suggests medium mixing for 15 minutes...