I think these protest (and any criticism of the WT for that matter) could be MOST effective if it simply provided information.
LEAVE THE COMMENTARY TO THE INDIVIDUAL!!!
That was (and is) the genius behind Quotes' site.
The WT is built on a foundation of bad or omitted information. All that has to be done is make that information known. That is it. There is no need to condemn the WT, their words and actions condemn themselves. Any philosophy that has as one of it's tenets that a group of people have a monopoly on absolute truth will always crumble under the weight of it's internal contradictions. The WT is no different.
So for a protest to be really effective, it would be good just to have some simple and humble signs (if that is possible) that say things like?
"Got Doubts? freeminds.org"
"Does Anybody Else Have These Questions? jehovahs-witness.org"
"If it is the truth should I fear asking questions? jehovahs-witness.org"
Stuff that ridicules or attacks or is snotty or condescending will only feed the cult genes.
It is difficult I know. We all have lost so much to this bunch. Our instincts are to attack. But nothing hurts the WT more then opening a closed mind.