Meat with garlic powder; place in slow cooker. Mix beer and half the barbecue sauce until blended; pour over meat. Cover with lid. Cook on LOW 8 to 10 hours (or on HIGH 4 to 5 hours).
Mix vinegar, mustard and sugar until blended. Add to coleslaw blend; mix lightly. Refrigerate until ready to serve.
Cooked meat to cutting board, reserving sauce in slow cooker. Pull meat into shreds with 2 forks. Discard all but 74 g sauce (or 24 g sauce for Trial Recipe) from slow cooker. Add shredded meat to reserved sauce in slow cooker along with the remaining barbecue sauce; mix lightly.
For each serving:
1 slider bun with 85 g meat mixture and about 20 g coleslaw just before serving.