Hey Triple A,
I appreciate what you are trying to do. Trying to reach JWs at assemblies is not very effective. JWs are conditioned to believe that everyone who is an opposer at an assembly is a wicked evil apostate of the worst kind. They will avoid you like the plague and look at you with absolute horror and distain. So, it is not a very effective method to open the way for conversation with any JWs. I wrote a topic on this one a while back and got many good responses and ideas that might help a person if they were going to attempt this sort of thing. Basically it seems best not to approach it from a religious standpoint, but to just simply expose the WT for what it is--in a question format. I personally thought the sunshade idea was very good--it's in this link
http://www.jehovahs-witness.com/11/68587/1.ashx
good luck,
cybs