i decided to probe around a bit and all i can find is (other than the refs you stated you had) was a pic of 1750/16 it was in plain or lightly color painted finish with white sqares on the fuselage side containing the iron cross. it seems like the underside of the top wing shows a cross on white box. cant see the underside.theres not really much on the C.III, much more on C.I. It seems that the jack herris book has the most on this craft than any books i have.and i looked thru about 15 or more books.