I like the idea of starting with the blood issue- it's not so confrontational since its just a "what if.". It really shocked me to find out that if you allow all the fractions that are now considered a "conscience matter" that basically equals whole blood when combined. Do they think we are stupid?
The best strategy is to deal with one issue at a time. Don't confront either, merely ask questions. You want to claim that these questions came from a householder or coworker, that way you don't immediately get shut down as someone that's questioning the authority of the eight imperfect men on the glorified elder body in Brooklyn. Then you ask for his help, claiming that as you researched the topic you've gotten more confused about the issue.
Here's a tough question, claim that a householder with a fair amount of Bible knowledge asked you if the JW leaders, the Governing Body, are bloodguilty for the past deaths of people, including children, that refused transfusions of blood fractions that are now evidently acceptable to Jehovah. Ask him his opinion on "blood guilt". Have him explain what it means to you.
"United in Worship of the Only True God, 1983, p. 155
The Scriptures show that if we are part of any organization that is bloodguilty before God, we must sever our ties with it if we do not want to share in its sins. (Rev. 18;4, 24: Mic. 4:3)"
Or ask him why Jehovah would feel that injecting blood fractions from "worldly" people into your body is acceptable, but donating your own blood before surgery, and then putting your own blood fractions back into your body is a disfellowshipping offense. Where is the logic behind that Watchtower rule? Would Jehovah really feel that it's wrong to use our own blood to sustain our lives?
Keep in mind that certain issues might not resonate the same with all Witnesses. For example I've seen several Witnesses truly bothered with the Watchtower's specific rules on shunning, yet other JWs coldly accept it and don't appear to be troubled at all. But those same Witnesses that are able to stop having natural affection for family members might be bothered when they realize that according to the Watchtower, Jesus Christ is not their Mediator. Or they might be bothered by the many changing "truths" on the generation of Matthew 24:34.
I'd recommend JWFACTS.COM, if you haven't already been there. The book "Combating Cult Mind Control" by Steve Hassan is also a great resource for anyone that's been in a high-control religious group in which the leaders claim divine authority. I realize that the book's title is provocative, but don't let that turn you off. It contains a ton of valuable information, just don't let any JWs see you reading it.