It's often referred to as "push moulding", as you push the master through the hot plastic. The key part here is for you to create an accurate master from something. I'd suggest getting yourself a block of Sculpy, and having a go with that first off, and if you can get it to look right, bake it & use that as the master.
If you can get your hands on another kit of the same scale, you could use that, or perhaps even take measurements off a different scale kit canopy to help you make your master more accurate.
You've got a big job ahead of you though, whichever method you use - good luck!