Thanks, glad you noticed that part. I'm trying to get away from static wing anatomy (always open and wing skin fully stretched), it only makes sense that they would crumple up and fold onto itself. Here...I was imagining it like fabric, like a blanket.
I see. Fabric is good choise, but again, here comes drapery still lifes. Hmm, for advice... Hm, If I were you I were looking for bat photos and pterosaurs recontructions. [link] To achieve more natural efect easier.