In a large bowl, stir together buttermilk, wing seasoning, and hot sauce. Add drummettes and be sure all are coated. Cover with plastic wrap and refrigerate at least 3 to 4 hours, preferably overnight.
Set up grill for direct cooking over medium-high heat. Oil grate when ready to start cooking. Remove wings from refrigerator and let sit at room temperature for 30 minutes. Grill 12 to 18 minutes, turning occasionally, ending with skin-side down.
Serve with ranch dressing, celery sticks, and cucumber slices.
INDOOR: Prepare wings as directed. Preheat broiler. Place wings on foil lined baking sheet or broiling pan. Broil 15 to 20 minutes turning occasionally or until cooked.