OCTO, you apply the plugin to a selected area. This can be done note-wise, measure-wise or on the full document.
If you put the plugin also on keyboard short cut, then you only need to call the short cut and enter return.
The plugin will always use the last settings. So even if you call it measure-wise it's just two keyboard hits.
If you select an articulation/expression that mimics the quarter-tone style, you don't even notice that it's not a real accidental.
For example something like this (the first one is unlinked from the part):
In that case you can apply it at the very end as they are not really distracting.
Here is another demo of entering three measures with quarter-tone accidentals using expressions assigned to metatools./www.youtube.com/watch?v=KEaBfQCVg4c
In this demo the expressions are not deleted afterwards, but only hidden, so that they still do playback.
AFAIK it's not possible to handle quarter-tone playback directly through articulations and HP.
The only ways I know are through expressions or by manipulating the MIDI.
The disadvantage of expressions is that they need a "Set to 0" on the next non-modified note.
The disadvantage of MIDI manipulation in Finale is that it is more difficult to delete.