In a large zip-top bag, combine vinegars, honey, brown sugar, chili sauce, garlic, soy sauce, marmalade, salt and pepper. Add in drumsticks, seal bag and toss to coat. Stash bag in fridge for 2-3 hours (or overnight) to marinate. Rotating bag occasionally.
When ready to cook, preheat oven to 375°F. Cover a baking sheet in aluminum foil and spray with cooking spray. Remove drumsticks from bag and lay on baking sheet. Bake in preheated oven for 15-20 minutes or until juices run clear.
Meanwhile, pour remaining marinade into a medium saucepan and bring to a boil. Reduce heat to low and simmer for 5-10 minutes or until marinade is thick.
When drumsticks are finished cooking, preheat broiler. Using a pastry brush, coat drumsticks in reduced marinade. Broil for 3-5 minutes or until browned and sticky. Flip and repeat with other side.
Before serving, sprinkle drumsticks with sesame seeds and cilantro.