THANKS! I was also looking for how to select which chord diagram to show, this is great. I am guessing this does not affect the voicing of the playback, because this is just a chord diagram selection, the chord remains the same. And I am using ukulele chord diagrams.
I add my encouragement to add chord diagrams to the library, although it would need to be done such that using any of them would "define them in the song" so that they get included when sharing a song. I think this is especially important for ukulele, with just 4 strings it helps to customize...