Here I have illustrated what I think are the changes for Coupelet models during the years 1915 to Coupé1919.
I would like to correct for where I might be wrong in my assertions.
My early plaited Top has a rear roof that is similar to Center Door.
I Hills will divide 1915, 1916 "Convertible Coupelet.
And divide the 1917-1918 "covered Coupelet" .....?
(1917 "rounded top")
(1918 "flaited Top")
Here is a link to the 2014 forum in case you want to post your neat drawings over there:
Oops, I see that you already did, sorry.