I’ve been using the Helmholtz-Ellis Just Intonation accidentals, and the playback is fantastic, especially with NotePerformer set to non vibrato. As Jude says, you must combine glyphs for each new accidental, and set its playback pitch accordingly, but then it works great.
For a Ben Johnston piece I’ve been transcribing, I’ve had to make about 100 different accidentals, which gets to be pretty time-consuming. Someday it would be amazing if Dorico could allow for multiple accidentals on a note, and figure out playback pitch automatically. That would be a dream come true, but it’s already amazing to put in music and hear the correct intonation without plugins, pitch bends, etc.