I have left my Wilsonara in water for 3 days before, and it did plump back. That is the Oncidium that taught me just how thirsty these Oncidiums go during our hot and dry summers. So I now give them lots of water, especially during summer when we get too hot and dry.
Going back to that Onc. Sharry Baby, I would still have kept it in its container with its media and drain holes and sink it in water like what you have there, leave it in water up to root zone for 2 to 3 days and remove the main container to allow them dry out time again. They love water but certainly good air circulation after a good dunking, and by then the media will still be wet, so roots still going to stay nicely moist, and not getting too disturbed as it gets water dunked.
