Backing vocals key

Hi folks.  Just downloaded the trial version and am struggling with something. I want to copy a vocal track which is my voice and then put AI on the copied track.  The plan is to have a female voice singing along with me providing backing vocals on the chorus.  But I'd have to say the AI vocal is really out of key with my voice. I've tried turning the “transpose” knob but it really isn't helping.  If I turn the transpose too much the AI voice just sounds awful.   Do you know the best way to put AI on a vocal track and have sit in nicely with your own voice?   This is the real reason I want to use AI voices.   I just need some backing vocals as my own voice is the main vocal. 

Thanks.

Xave