I agree with Missing Link on setting a deadline if you attempt this. There are success stories and failure stories on both sides of this issue.
It is a personal decision wrought with misgiving either way. You either think you could have done better at helping or you think you wasted so much time more in helping. So if a person is up to the challenge, it's their time and life. If they need to look out for themself, it's not their responsibility to "wait." And sometimes, getting out of Dodge is what the members need to see. Some surprise might make truly concerned people look into the matter.
As a quick fader, I will say this. Being a free-spirited JW, getting family to the point of being considered weak JW's: that would be good. But staying at such a point is really not a whole lot better than them being staunch JW's. If an attempt stalls at that point, I would recommend just finishing the fade and seeing how a person could help from the totally inactive side for the rest of the attempt.
I also point out that, if children are involved, my opinion is to get the hell out much faster for their sakes. Why should they be getting more and more cult indoctrination while a parent is playing the game to help other adults? Children deserve to know right away that there is nothing wrong with wanting to do "worldly" things like skip church, eat birthday cake, have fun at sports, go to college, etc.. I would recommend less than a year for a deadline when children are involved. I suppose an exception could be made if they are able to handle the parent confiding in them that it isn't "the truth" and we need to help Mom/Dad/Grandma or whoever out of it.
Friends- it is my thought that friends can only be helped if they are ready to be helped. Set a short deadline, then expect to lose their friendship. Sad, but it is the norm. Staying behind for their sake more than a few months is really hurting yourself.
Those that come to a realization about the religion typically cannot do any of this. They need to fade, walk away, resign, or be kicked out. This is only for the few that are ready for such a tough assignment. No shame in either course.