I'm doing Asuna's blue outfit from the very end of the show and I don't really want a glassy look. Like I said before I want them to look lighter and softer which is why I don't want to use thick plastic. Plus the wings always looked matte to me. Example
(even though those wings are photoshopped in)
I wasn't thinking so much organza as a stretch fabric because I don't want the effect the organza would give, especially since organza is shiny and usually doesn't lay very flat. Though tearing organza isn't a very easy task (at least the organza I use).
Both my friends and I never saw Asuna's wings as glassy and I don't think hard wings would go well for either of her ALO outfits. They never gave the wings a reflection or shine to them as far as I saw in the show, so maybe that's why I feel that way. Maybe a matte acrylic, but I wouldn't use anything shiny for my cosplay and I feel like it might still be too overbearing. To each their own I suppose.