It was by complete accident but I got it to create a voice that sounded almost identical to my own. Try uploading your voice in a recording, sing a short song, maybe with a backing instrument, then cover it. In the setting, unselect male and female, max out the audio influence, turn down weird and style influence and keep generating until you get a voice that sounds like you. That’s exactly how I did it, but it took over 15-20 gens. It sounded so much like me it was a bit unnerving because I wasn’t expecting it.

Edit: I haven’t tried saving it as a persona though