i use Diatonic mode for harmony leads in 3rds. Don't bother with a unison just turn the "Pitch mix" to "Pitch A" only and the Mix knob half way or however much wet signal you want. If you add a Tiny bit of delay, like a couple of micro seconds, it helps with the tracking IMO.

the second question is tough. There is a baritone preset somewhere from banks 18-22; Pitch flex. As much as i love the pedal it doesn't do detune well enough for me (i still see it as a monophonic effect). i've saved a preset to pretend i'm a bass player but in no way would use it to record or live settings. if you go to the pitchfactor support page you can download a pdf with all the presets levels graphed out.