Combine dry seasonings in a small bowl and evenly rub over fat-trimmed roast.
Place meat in a 6-quart slow cooker.
Mix water, soup base and liquid smoke in a glass measuring cup. Heat in the microwave on high for one minute, stir and then pour over roast.
Cover and cook on LOW for 6-8 hours (or HIGH for 4-5 hours) or until pork is very tender.
Place pork on a large cutting board or platter and let rest for 10-15 minutes. Pull, slice or chop to serve.
Serve on toasted buns with barbecue sauce, fresh sliced onions and fresh refrigerated pickle slices.