Question how much that flare-up actually messed up your chicken, because a little char can be fine tbh. Offsets are unpredictable beasts and flare-ups happen when grease hits the coals, it's not the end of the world. Just keep your fire managed and maybe adjust where you place the bird over the heat. Everyone gets obsessed with competition rules but honestly some of the best BBQ comes from happy accidents. Relax and nail the basics before worrying about every little flame.