A Club Member has found a detailed article by two of the key Engineers who designed the original NA MX-5. Toshihiko Hirai and Shinzo Kubo were the Product and Project Managers. They prepared a presentation to the Japanese JSAE (Japan Society of Automotive Engineers), in October 1989.
It explains while many design decisions were made and amongst other detail gives graphs of lateral acceleration / camber change and compares yaw inertia with FWD competitors.
This is unique information directly from the horse’s mouth, as it were and not fileted by journalists or passed on third hand.
Download the pdf file here: MX-5 Technical Article JSAE 30.07.2016