"If, however, you discover the ultimate argument that is so subtly devastating as to shock one Jehovah's Witness after another into reality I will gladly donate $1000 to your bronze statue."
You simply have to eliminate their resistance to talk to apostates. If you can break that barrier you have a chance. Comparing the WT warning against apostates to a wife beating husband warning his victim wife against people who will say he doesn't really love her is a devastatingly effective argument. It paints a picture many can relate to, and nullifies the catch all defense of "I was warned smart people would try to convince me!"
Essentially, if you can get your target to admit that a man who beats his wife is evil, and the beaten wife who blames herself instead of the husband is misled, you now have a wedge that you can move back and forth until they get it.
They will never admit it immeadietly like you say, but over time I think this will eat at them.
The only way to truly "shock" witnesses into reality is to buy time slots for a short 30 second commercial on national television.
If you make the commercial too long, they will be warned against it by the society, so you have to make it so brief that by the time you find the remote it's over and the message has been played.
The message should be something short and simple, like the example I gave above. It should be illustrated visually and not revealed until the end of the commercial that it's even anything to do with an oppressive religion. This tricks the guarded viewer into watching it before they have a chance to shut the information down, and connects them emotionally with the message.
Why is this effective? Because unlike a valid argument after someoen has received doctrine, they have a defense built up. Once you receive the WT doctrine any information you receive is heavily filtered.
When you receive a message without realizing its relevancy until later it's almost the equivalent of the "born in" witness having a moment of clairty when they hear how it applies, since they did not have their filter up when they received the message.
For example, I tell you a thirty second description of a graphic love scene. At the end I say, "by the way, the story was about your ex girlfriend and her new boyfriend last night"
Now it's stuck with them, they were forced to listen.
If you guys are interested in making a commercial someone should start a kickstarter campaign. I feel bad though because it will ultimately result in the WT banning television lol.