Nice job! I personally would not try to communicate after your initial reaction. Great work noting the license plate...even if you have to pretend to take a plate number to give them a little scare, do it.
I have had an ass buzz me like that, my uncontrolled reaction was to yell and the finger. He squealed to a stop and started to reverse back to me at high speed. In that situation, I shifted into my small ring and pulled into the grass and did a dismount. My plan at that moment for a fight was to stay in the grass so I would have cleat traction and to use the bike as separation with the big ring out as a weapon. He peeled off without further incident.
I really need to get some pepper spray or mace for these situations, just in case. If anyone buys this stuff, get the foam as it helps with not hitting yourself with overspray. For now, I am ready to pull out my c02 kit and warn them that I am going to mace them with it if it happens again, but I plan on getting a real canister. Lord knows I could use it for dogs as I nearly got clipped twice on saturday.