“Okay, Zakk, it’s time!” As the morning sun begins to break over the Texas hills, Dimebag Darrell thrusts the keys to a waiting sports utility vehicle in Zakk Wylde’s enormous hand. All through the night, over countless shots of Blacktooth Grin -- the particularly potent and tasty mixture of Crown Royal and Coca Cola that flows like water at Dime’s Arlington-area compound -- the Pantera guitarist has been psyching up Ozzy Osbourne’s right-hand man for this very moment.