I'm talking about from the wearer. Simulate what singing into a face shield would do to the rest of the room.
So in your experiment are you suggesting spraying at the inside of the shield from a distance of 1", 2" or 3".
Anecdotally, at the LTC facility where my mother stays, they provide the residents with face shield for encounters with visitors. Visitors are required to wear face masks (I don't know what would happen if a visitor tried to come with a face shield) and maintain a distance (all outdoors, for no more than 10 minutes, 1 visitor at a time). 0 infection rate in that facility.