I though I could make a separate database picker for it.
The first issue is the Style Picker in the Custom Midi Style it does not have the 4 bar preview like in the normal Style Picker.
The next issue if you go into the normal Style Picker and try a midi style track by soloing it and click 4 bar preview it will work good and give a preview but when you "Cancel" out of it it still leaves the midi style loaded rather than going back to original style.

So I made this up, give it a try and see if it works okay for what you need.
It's just brought up by right click a track > Custom MIDI Styles for Tracks/s, so whatever instrument you check will play preview with your chords and you can set it to any track, it will also preview multiple checked tracks along with your existing tracks.
It's a free floating non jail window so you can adjust volumes, mute or solo tracks in the Mixer while it's open.
It uses existing code copy and pasted into new picker.
You maybe able to make an option to just generate for selected bars in the chord sheet.
It should preview with whatever Plugin or default synth is on that track.

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