I probably did 3 layers but it probably would’ve been fine with two as the first coat did well. I only used rubbing alcohol to prep and that was it. I also had a GMC parts guy say all they do to theirs is paint them. That Krylon Fusion All-in-One was recommended on another video I watched before doing my flood light chrome outing and the chrome piece by the side of the hood behind the side mirror. Both of those have held great for over 8 months. I only did the sensors about a week ago when I finally replaced the black plastic caps over chrome with a full black bumper but have had no issues with the sensors since then.