The mistake you are making JWA, is to assume the bible presents a coherent Christology. If we read the letters of Paul and then the gospel of Mark, then the synoptic gospels and finally the gospel and letters credited to John we see an evolution of doctrine from Jesus a man anointed by God to Jesus the Divine being.
The trinity is nowhere described in the bible; it is a post-biblical construction.
A more promising approach is to show JWs that their relationship with Jesus is radically different from that enjoyed by early christians.
Jehovah's Witnesses View of Jesus Compared to the Early Church