He should confine himself to questioning and exposing her policies, lies, and ethics. Everything else will take care of itself. Do not get drawn into a marble shooting or spitting contest. Just stay focused on her ethics, lies, and policies as if they were the only thing in the universe. Do that and everything else will take care of itself. He did that well in the debate. They already know how to push his buttons. He just needs to stay aware that they know how to set him off and not fall into their stalling and deflecting traps. Heep on the Hillary ethics, lies, and policies trail and he will have ample time for revenge later.
I don’t disagree with what you are saying. He is on message. Part of the message is Hillary’s bad judgement.
Read the tweets. There are three, and they attack Hillary’s lack of judgement, which is one the “issues”.