OK, I'll throw yet another idea out there....

You can get an iron-on tricot; extremely light weight. So much so you can hardly tell it's there. I've used it many times, for all different applications, and can't even tell where I've ironed it on. Not 100% sure of the silk, however, as I've never used it on silk. But it's something I'd try, to see if you liked it. It's found in the interfacing section of JoAnn's. (I know silk can be a real hassle!!)