Hey Superjedi,
That's a great tutorial! But if i may, before tracing any outlines on your carbon paper you could use the computer to "horizontally flip" the template. This way you won't need to trace twice the same outlines (gain of time!) and it will reduce the risk of slightly deforming the damage areas.
Also, what kind of pencil do you use ? A classic graphite pencil? And if so, what do you use to wipe the markings from the helmet once done?