If I may, the design for construction of the door is a PF design, not a Lancia design.
That said, I have had a few PFs, and seen many others. When they are right they look and feel magnificent, but metal gets tired. Door sag can be an issue, and poor refitting, with one
corner not quite flush, absolutely spoils the surface.
That won't be the case for Hubert....
As to what is "really required", that's rather subjective, no? Myself? I'd favorably compare Lancia engineers against most contemporaries.