I've tried using my IPad with notes to control the presentation while preaching, but found it a bit buggy and unstable. Also, the lack of ability to increase the notes font glues me too tightly to the screen.
Hence, I've gone back to using the IPad for just my notes, and advancing my Powerpoint slides with a remote clicker.
However, we have no wired confidence screen, so I do not know what is displayed behind me without turning around. So - can I log in on the phone app just to see what slide is current - while still using the remote clicker to advance the slides? Not the best solution, but perhaps workable?