I'm with 13doctorwho on this. If I were building it, I would be looking for Catwoman or Black Panther cowls/masks (since those are more popular characters and, thus, more likely to have been done before) and figuring out how I could either cut away or add to certain aspects of the existing template to make it more specific to Hellcat.
I recommend searching out some of the Pepakura and foam templating artists we have here (JFCustoms and Blackkaos come to mind) and seeing what they have to offer in terms of existing templates that you could use as a base.