Prepare grill with hot coals around sides. Place foil drip pan in center.
Combine garlic salt, chili powder, paprika, oregano, cumin, allspice and red pepper in small dish. Reserve 2 teaspoons for Margarita Salsa Verde.
Remove all but 1/4-inch layer of fat from pork. Sprinkle Dry Rub over pork, rubbing in.
Position grill rack 6 inches above coals. Place pork on rack over pan.
Grill, covered, for 3-1/4 hours or until meat thermometer inserted in pork registers 165 degrees F. Add briquettes to each side of grill every 50 to 60 minutes to maintain heat. (You may add soaked hickory chips after the first hour of cooking.) Let pork stand 20 minutes before slicing.
Combine cumin, reserved 2 teaspoons Dry Rub, bottled salsa, lime juice, cilantro, and tequila and triple sec if using, in a medium-size bowl.
Slice pork and serve with salsa. Garnish with fresh cilantro and lime wedges. Makes 14 servings.