Thanks, y'all! Thanks especially for that clip, Valkyria. I've got the episodes and plan to take copious notes.
Meanwhile, I did a slap-dash mock up of the cowl/mask. The sides need to be brought in and front brought down, and I'm going to have to figure out a back closure (probably velcro). Overall, though, I'm generally pleased with the shape. The fact that it's bubble gum pink is my gift to you.
(I was using that fabric to mock-up something else, so it happened to be handy. Also, I like pink.)
I also found good fabrics for the dress and cowl (heavyweight cotton jersey and mid-weight spandex blend, respectively) and a basic pattern to work from:
(With adjustments, obvs, including getting rid of that weird hood.)
For the sash, I have some nice red broadcloth handy. The color is absolutely perfect, but I'm not sure about the drape. Will have to test it and see, so fingers crossed.
The other thing I'm pondering, atm, is the make-up, which I'm sure is a challenge for everyone whose done this costume. What's got me is the skin color. Is it greyish white or a very very pale slate grey? I've done solid white make up before, and I'm wondering if I can get the right effect by doing a white base and layering light blue-grey shadows over it, or if there's a way to get a close enough shade, either pre-made (Mehron's Moonlight White looks promising?) or by mixing. I've got an airbrush, which I suspect will turn out to be useful. Any input on this will be much appreciated.