I only now noticed that you discussed this with Daniel as long as three years ago. I was in contact with him, on the subject of microtonal notation, about one year ago. What he wrote indicates that using a JI notation system in Dorico with correct playback will be difficult, and probably impossible in Dorico’s own (still nonexistent) microtonal playback implementation:
“Our plan with support for microtonal accidentals is to allow you to define your own system of accidentals; the only practical restriction is that the system must be expressable as an equal number of divisions of the octave.”
And:
“I’m sorry that we’re unable to accommodate just intonation tuning systems completely correctly in our application. We did talk about it at some length, but [–] the complexity of supporting arbitrary unequal divisions was judged to be too great at this stage.”