You’re making this WAY more complicated than it needs to be! Yes, get SKU27. Do follow the steps for taking out the old anode and installing the new one. Flushing is not a bad idea, although without a flush kit, it will have limited success. Skip the peroxide and heat. As soon as you remove the sacrificial anode, the odor will start to dissipate, and the bacteria themselves are harmless. They’re already in the cold water and you wash in them and drink them all the time. It’s only when they party with sulfur and sacrificial anodes that they become stinkers.