Here are the photos of the shell showing an overview, and what to improve.
As you can see, the square shell increases the thickness. Comparing with the DIY shell of @Zimmy , it seems that I have something more imposing, and less rounded with this 3D shell :
I tried 3D rendering with TinkerCAD (open to beginners) but nothing works: I can’t easily modify the original STL file due to lack of skills, so I made a sketch of what I want to correct on the original STL file, based on my previous feedback :
Question :
Does anyone have the skills and time to modify the original STL file according to my recommendations? That would be really great, and we could add it to the Purism git webpage !