Great read. I really like to read about experiences with speaking to JWs.
In my experience of talking to them when they come over, they have a narrow scope for a basis of conversation.
They first assume that you believe in God, and next they assume that you believe the bible is true. From that starting point, their training is really geared around convincing you their interpretation is better, as opposed to other christian sects. It's always been like that since the beginning of the Washtowell.
The moment you take it a step back, and claim are you not convinced God exists and that you don't believe the bible is the word of God, their entire baseline is demolished. All of sudden, reading verses from the bible is pointless, since you don't believe in it. What to do? They usually look completely disarmed, perhaps making a tepid argument that revolves around "how did everything come to exist", or "who created everything", as if that helps them in any way.
I usually ask ... "Why do you think the Bible is true?", which really gives them a hard time. Typically they resort to bible prophecies which easily can be made to look silly, when you point how vague they are