The Watchtower argument is more geared towards defeating Modalism, not the Trinity.
Listening to my friends attempt to discredit concepts that they completely misunderstand makes me cringe. I recently got the challenge question ..."if Jesus is God, how could He have been here on Earth?" It appears that leveraging the name "Jehovah" has made "God" an individual unit. My friends don't get that the term "God" is used interchangeably as a noun (Father) and a description of a nature.
Given your writings, you may be able to help me.
It makes sense to me that Jah was the [man] before Jesus, then when Jesus came Jah gave the whole mess to his son.
According to that which you know, when was this power transferred? And how do we make this fit with John 1:1-3?
Let me know... :)