I've not done a full sized silk quilt, but I did some small projects with silk dupioni and a wool batting -- such a beautiful combination for showcasing your quilting. I used a cotton backing since they were for cushion covers and small bags and the backing would not be showcased.
I think in your place, I would do some small scale samples before settling on my choices for the big project-- see what effect you like best. you can always use your sample pieces to make a pillow or a table runner.