Preheat the oven to 235°F. While the oven is preheating, rinse the pork shoulder under cold water and pat dry with a paper towel. Then, mix together yellow mustard and one tablespoon of liquid smoke and evenly coat the entire pork shoulder.
Mix the spices for the smoky seasoning in a shaker bottle, and liberally season all sides of the pork shoulder. Set the pork shoulder on a wire rack (sprayed with nonstick cooking spray) inside of a raised edge baking pan. Add hot water and liquid smoke to the bottom of the pan and place the pork in the oven. Roast for six hours
Remove roast from the oven, and place on a triple layer of aluminum foil. Add one cup of the liquid from the bottom of the pan, and seal the aluminum foil as tightly as possible.
Place the pork back into the baking pan, and return it to the oven. Increase temperature to 250°F and allow it to cook until the internal temperature of the pork reaches 205°F as indicated by a reliable quick read thermometer. About two more hours.
While pork is cooking, mix all ingredients for the BBQ sauce in a large saucepan. Heat over medium low until the sauce thins and is warm through, set aside
Allow the pork to rest for at least 30 minutes to one hour. Then, pull the pork into desired sized pieces. Serve hot with the smoky BBQ sauce.