That's great. Another great method that might work is the planned planting of seeds with the intention that they will be watered at the kingdom Hall later. What you do is you look ahead to what topics will be discussed at their meetings in upcoming weeks. You single out a false, extreme or otherwise objectionable point that you notice in the upcoming material. Then, in conversation with the JW, without mentioning the material, you make logical points that undermine the point in the material or that will expose it as extreme or wrong. The seed is planted. When the JW has the meeting and the pertinent material is being discussed, it will remind hopefully remind him of the points you made exposing the reasoning in the material as wrong. The seed is watered. Do this enough times and soon the JW will begin to see the flaws in the religion and start questioning and doing independent research that will hopefully wake him up.
Here's an example of how this can be done:
At last week's Watchtower study, the following point was made:
"For example, the July 2009 Awake! suggests that if a classmate asks: "Why don't you believe in evolution?" you could simply reply: "Why should I believe in evolution? Scientists don't even agree on it, and they're supposed to be the experts!" - The Watchtower, September 15, 2014 page 16, par 18.
This is clearly misleading and fallacious reasoning. Scientists are in agreement on the fundamentals of evolution. They differ only on gray areas related to the evolution of some individual species, for which there's not much data available yet. That they differ on minor side issues, is not sound reason to disbelieve the fundamentals of the theory of evolution, for which there is much evidence and wide concensus. So the above quoted material is an example of Watchtower using false reasoning and training children to use false reasoning. So imagine you have read this material in advance of the meeting and you have opportunity to speak to a JW. You could strike up a conversation something like this:
"You know, Sis. Dub-fire, this guy at work was telling me that he doesn't believe the bible. So I ask him why. He says to me:
'Why should I believe the bible? Not even religious people can agree on what it means, and they're supposed to be the experts!'
So I say to him:
'But bible-believers do agree on the fundamental points made in the bible, things like: God created all things, there's only one true God, Jesus is God's son, Jesus died so that our sins can be forgiven, Jesus was resurrected, etc. The things they disagree on are mostly things that aren't made explicitly clear in scripture. Look, there are many things that scientists don't agree on in every detail but that doesn't mean its not true. For example, scientists may not all agree on the true, fundamental nature of light - whether its ultimately a wave or a particle - but that is no reason to disbelieve the existence of light, is it?'
What would you have said to someone telling you they don't believe the bible because religious people don't agree on it and they're supposed to be the experts?"
So you get the JW thinking about how this guy at work is using false reasoning. You even get the JW to think of how he/she can refute such false reasoning - you get them mentally invested, to take ownership of the logic that refutes such false reasoning! Thus the seed is firmly planted in the JW's heart. Now imagine what happens a week later at the Watchtower study when he reads identical false reasoning in Watchtower material! It would seem eerily familiar somehow and he will be able to spot that the reasoning is false! The meeting would have essentially germinated and watered the seed you planted!
Just a word of caution though: one should avoid doing the conversation with the JW, too soon before the material is covered, as the JW may have already studied it in advance and may catch on that you're trying to discredit the publication on the sly. It's best to have the conversation no less than one week before the material is covered. Even if the JW forgets the conversation he had with you, his mind would have been trained and prepped to see the material as being questionable.
I call this method Preemptive Sensitization to Identify Cult Crap (PSICC (pronounced "sick") for short)