There are extensive threads on Malta both here and on the Axis history forum. A little searching will turn them up and allow you to proceed from there in a more informed manner. One thing you are apparently neglecting is that changing production can have a big impact on production. The US went to a considerable effort to minimize that impact. Shared parts between various vehicles helped to a great extent. Not much way to minimize it if you go from an Italian to a German design. Likewise major modifications can have a bit impact. That sort of industrial planning hasn't been noted as a strong point of Italian industry.