Does Lee's "Headstrong" disability activate when he reveals himself to be a Cylon, or does he get to choose which cards he discards to get down to his new handsize?

I've always played that he discards normally since revealed cylons ignore their player cards. However, it occurs to me that I could have been playing it wrong.

Well, I think you are right - its how we do it and on the same logic basis. He reveals first and becomes a cylon then, cylons ignore their old player card limitations so discard by choice.

I did get an official response from Mr. Konieczka, as follows:

His ability does NOT apply to this [discarding down after revealing]. As soon as Lee reveals his "You are a Cylon" card, all of his character abilities are ignored.

I hope this answers your question!
-Corey Konieczka
Lead Game Designer
Fantasy Flight Games