In pint-jar with tight-fitting lid, combine sugar, paprika, seasoned salt, chili powder, black pepper, celery salt, onion powder, garlic powder, ground sage and dry mustard. Place lid on jar and shake jar to combine thoroughly. Set spice rub aside. Makes about 1 1/2 cups.
In small saucepan over low heat, stir together barbecue sauce and honey. Heat through, stirring occasionally, about 5 minutes. Set barbecue glaze aside, keep warm or at room temperature before using. (If storing for more than 2 hours, cover and refrigerate. Reheat gently before using).
Pat ribs dry with paper towels and season generously with spice rub, using about 4-6 tablespoons for each slab of ribs. Grill over indirect heat in a covered grill or smoker for 1 1/2 to 2 hours. Turn ribs once during cooking, about halfway through. Ribs are done when the meat is very tender (insert a paring knife between ribs to determine); they will pull apart fairly easily. About 20 minutes before ribs are done, baste heavily with barbecue glaze. If you like your ribs extra sticky, baste again 10 minutes before removing from the grill.