Update on this project:
A fellow modeler sent me some drawings on the Gallaudet company and its proposals to the navy, circa 1916. One of the designs was called the Hydro Scout. Although never built, this is a very appealing design because of its simpler construction.
With a 28ft wingspan vs 48ft for the D-1, I can make a 1/4 scale model rather than 1/6th. It will be a larger plane but considerably less wingspan, important for me to transport. I will attach the drawing and size comparisons (rendered D-1 to white lines for the Scout).