Find the Twin Airplanes -- April 2, 2013

From the May, 1929 issue of Motion Picture Magazine. "Here are ten pictures of the 1929 90 h.p. Waco Airplane..."  I think I know which two are the twins.  Would anyone like to offer an opinion?  I can't offer an airplane or cash if you get the right answer.  Be sure to click on the image to see a larger version.