Dan - see this old thread for pictures on twing locations: https://j30.us/ubbthreads/ubbthreads.php/topics/4896/Re_Spinnaker_Guy.html#Post4896

And this recent thread: https://j30.us/ubbthreads/ubbthreads.php/topics/7013/Spin_Sheets_through_Second_Blo.html#Post7013

Twings are useful for control but could be eliminated in light air.