Because you have nothing to lose, you have an opportunity to share TTATT with other JWs in your congregation. If I were in your position, here's what I would do:
I would do up a very friendly letter/email making it the least confrontational as possible and use it to tell all the JWs in my hall that I love them and wish them all the best but I cannot in good conscience continue to have my name associated with the Watchtower organization because of certain indisputable facts that have come to my attention.
Then I would proceed to very mildly explain several of the most damning and undeniable bits of TTATT, supported with quotes from the bible, Watchtower publications, official Watchtower letters/documents, court transcripts, and/or other evidences. I would share things like: Watchtower's official policies geared at covering up incidents of child abuse from others in the congregation and the police; Watchtower's history of false prophecies and presuming to speak in the name of God things he did not say; Shunning disassociated ones who commit no gross sins; examples of glaring dishonesty and misquotes in Watchtower literature; etc
It's very important however to word it as mildly as possible, making it, not so much an attack on the organization as much as an explanation of why my conscience, personally, does not sit well with it.
I would state that my reason for telling them this information is not to try to pull them away from the organization but to prempt any rumors that may result from the elders announcing "[My name] is no longer one of Jehovah's Witnesses" without informing the congregation how or why this is so, leading many in the congregation to speculate and foment vicious rumors that tarnish my reputation.
Then I would end the letter by saying that I love them as individuals regardless of their religous beliefs and do not wish to let a difference of conscience on religous matters be a basis for ending my friendship with them as I think friendship is not something you throw away over a difference of conscience on the matter of religion; but I understand and forgive them if they feel pressured by Watchtower rules, to shun me over the matter of simply not wanting to be associated with the Watchtower organization.
I would send this letter/email to as many JWs in my hall as possible, except for the elders. If it's an email I would send it out about 1 week before sending in my DA letter to the elders. That way I let the rank and file know the details before the elders - my way of turning the table on the Watchtower's policy of having elders keep the details of JCs private from the rank and file JWs, when an individual only DAd. Yes, I would go out with a bang and I would also make it known to as many as possible that I have not been disfellowshipped for some sin but left on my own volition because of the unbearable stench of Watchtower! But that's just me.