Hi, several months ago I started the restoration of an Aecy Ducey project that was located in a barn where it was stored for over thirty years. The project was never completed. recently I discovered that it is nearly impossible to easily enter and exit the rear cockpit -- flies from the rear cockpit. I had an aeronautical engineer friend draw up modifications to the fuselage tube design that would allow me to cut a segment from the top longeron and install a door smaller, but similar to the door installed in the front cockpit as part of the original design.
My engineer friend urges me to find some kind of data that would verify his design. I'm looking for examples of vintage aircraft that have doors installed in tandem, steel tube structures. Does anyone have any suggestions where I might find this data? I was informed by the EAA Hq. folks the the Baking Duece has two doors and I am looking for info on how the fuselage is designed to allow the rear door.

Thanks for your help.