After months of experimentation, a few hundred bucks spent on materials, and a lot of pain mixing colors, I think I've FINALLY nailed down the cape.
Hard to tell from this photo,but the colors of both the inner and outer skin are looking really REALLY good. There's a black streak in it where I didn't mix things up properly, but since it's just a test, I'm not worried. I'm really happy with the deep shade of red I got. Almost like plum. Very cool looking. No brown to it at all, like I was getting with the Burman pigments.
But yeah, everything else really came together. Next step is to mix up a big batch of the right color, and go to town on the thing. Great news all around for this project!!