I live in Milan, let me know when you are in Italy, it would be a pleasure to meet you.
About the 3D model, I don't own all the drawings.
For my workflow I started in 2015 to plan the 3D model basically relying on the several pictures available mainly on this forum and in general on internet and taking advantage of the huge capability offered by CAD software.
Main issue in this modeling was to get an absolute reference for the dimensions.
In 2017, after some design iterations, I was quite happy with the results but not sure about the correct measurements, so I planned to buy the body shell before starting the chassis fabrication to finalize the model.
However at that time I saw an offer on eBay of a set of original drawings (I discovered recently a dedicated discussion on this forum on this drawings that however I have missed when it was active) and I decided to bought it (it was much cheaper than buying a body shell and it served better to my purpose).
This set of drawings is quite limited, it is about 10% of the total number, but it was very helpful to me for two reasons: 1) to set the correct overal measurements and to discover that my original model based on chassis pictures had an error lower than one inch

2) to discover the huge amount of fine details in the original drawings that cannot be catch from the pictures.
This is why at the beginning of my buildlog I defined my project just as "inspied" to the original one, because in my opinion a true copy needs to be based on all drawings to reproduce all the fine details.