Place chicken into a large resealable container.
Add enough buttermilk to cover the chicken. Add hot sauce, if using.
Seal and shake gently to coat the chicken and combine the hot sauce. Refrigerate overnight.
Fire up your Vortex. Fill completely with coals. You'll need at least a 22" charcoal grill.
Combine all dry ingredients and pour into a pie pan or alternatively, place in a large resealable bag.
Working in batches, remove chicken from the buttermilk. Shake off excess and roll in the coating. Alternatively, add the chicken to the bag, seal and shake to coat.
Place chicken around the edges of your grill. Cover and cook 30-45 minutes or until the chicken has reached 160 F as measured in several locations.
Lightly brush the chicken with the oil and cook another 5 minutes or until the chicken reaches 165 F as measured in several locations.