I know this topic is from a few years ago, but I'm doing Phasma this year for my Halloween costume, and maybe this will help out with the next person who does it. When drawing the arc at the bottom of the cape (in the original dimensions), you'll be drawing a portion of a circle with a radius of about 175 cm, with the center 51 cm down on the left side of the leftmost piece, which is what that mark on the diagram is for (I didn't realize that until I had worked it out manually, lol).
The build looks amazing, Brit, and thank you, this thread has helped me out a ton in making my own build. I'm not going for certification yet, but I aspire to it at some point.
Thanks again,
Brian.
