You could just make the cape and add the hood after. I opened the image in a new tab and I still can't really see it well enough to figure out what's going on.
You have to decide if the cape is a rectangle or a circle.
For my recent cape, I just held up some fabric to get an idea - the 60" fabric I held up was wide enough for the look I wanted and I had already decided that my cape was supposed to be a rectangle - so it was just a matter of draping it and measuring to where I wanted it to end.
I'd guess that hers is circular, from the way it is in the front. But I'd like to see a better picture of the back (couldn't find one) - to get an idea of what is going on with the hood and other details that are too small to see.
Disclaimer : This post written by a Grumpy Old Man
Actually in the pipes:
- Remaking Ser Loras doublet.
- Luke Skywalker, A New Hope
- Wind Waker starter costume in swim material
Eventually: Paul from Dune, Faramir, Harry Sullivan