it might be worth posting a picture so we can understand what you need.
HiThank you for your response . In the attachment I am sending my case to illustrate the problem. As you can see, my fender edge above the wheel has been cut and replaced by some non-original fantasy part from the previous owner. I would like to restore the correct shape of the arch, but unfortunately I do not know anyone who has the same car model in the area to make template. therefore I thought that if I had the distance of the edge of the arc from the center of the circle, my tinsmith could recreate its edge. I drew lines to show the distances needed to recreate the arc shape.
Another idea was to use the available sheet metal parts from the 105 model, but I'm not sure if the dimensions will fit. Anyone have experience using this shape on the Giulietta Sprint 101