Just my idea. You don't have to have the batting in the middle but you will probably like the outcome better. I would use something thin like Warm and Natural. There is also a batting that is fusiable and I believe there is a fusible fleece. Just don't know if it's fusiable on both sides. You could also hold together with a spray adhesive. This is all temporary until you done your tacking stitches. You would need to do some type of tacking even if it's with your decorative stitches on your machine. Like the * stitch. With the embroidered silk it might just blend in. Check the stitches you have and see what might work. When it is laundered it will separate if not tacked in some fashion. Good luck.
I would probably use something to make it a little firmer. But, since you are not quilting, you may want to use something that could be ironed on like a wonder under type of fabric.