I personally have found you can't fight a mud wrestler by jumping into the mud and grabbing at the champ.
First off, it is futile.
Jehovah's Witnesses don't get bested in a one-on-one because they won't engage you unless you accept their fundamental premise.
What is the fundamental premise? That the Bible is the inspired, inerrant word of God.
Once you stipulate that's okay by you---you're toast!
Why?
Everything which logically follows is INTERPRETATION.
You may as well try beating a Pokeman master by sending your Charazard against the JW's.
You CANNOT ACCEPT THEIR PREMISE!
It is a matter of indisputable fact that NO ORIGINAL AUTOGRAPH MANUSCRIPT OF SCRIPTURE EXISTS.
Nobody can deny this one point. The best that can be done is to try and convince you Jehovah "must have preserved" such and such...
That is a blind assertion.
Either Jehovah preserved or He did not preserve uncorrupt scripture.
The only thing that follows that admission and realization is this: IF JEHOVAH DID NOT SEE FIT TO PRESERVE (and He didn't) original, uncorrupt, autograph scripture---then all we have is unoriginal, corrupt, fraudulent writings PRETENDING to be genuine originals.
Got that?
When you look at the fragments of the earliest remaining bits and pieces of third generation writings (purported to be copies) NONE OF THEM MATCH each other.
What does that mean?
IT MEANS Jehovah did NOT see fit to PRESERVE an uncorrupt scriptural message!
What is the difference between a corrupt scripture and an uncorrupt scripture?
Answer: A clear starting point from which factual interpretations can be drawn!
Example: All JW's parrot what the Society says about how the death of the apostles ushered in a period of apostacy in the church. (Hint: they are talking about the Catholic Church). This is where the Watcthtower tells us various corrupt teachings got mixed in with pure worship.
The Church (under the aegis of Emperor Constantine) sought to eliminate discord and false teaching by convoking the Nicene Council.
The Watchtower Society points to the results of this council as the solidification of False Religious corruption in Christianity.
But, this SAME AUTHORITY produced the bible!
That bible consisted of 73 books. It was the ONLY christian bible until Martin Luther tore 7 books away and wanted to destroy more.
The PROTESTANT bible simply had fewer books (the rest were eventually marginalised and removed) in it and none of them matched exactly any array of latter-day manuscripts.
So what?
So, the premise of Jehovah's Witnesses that they alone have PURE WORSHIP is based on their interpretation of a corrupt fraudulent book purported to be PURE and INERRANT in truth and teaching. They pretend to be restorers of truth (and only gradually.....because of all their demonstrable errors in predicting the end!)
False premise in=False Conclusion out.
Fighting JW's by throwing scriptural interpretations against theirs is futile no matter how brilliantly reasoned.
When you fight JW's you are fighting the false-premise of their AUTHORITY TO INTERPRET THE BIBLE.
REMOVE the Bible (as an uncorrupt starting point for interpretation) and you remove their authority to control the worship of individuals and their direct access to God through Jesus.
The bible is a flawed manmade assembly of hearsay and cobbled Hebrew scripture.
That's my opinion.
Your mileage may vary.