I think interfacing might make the sheer too stiff, plus most sheers are polyester, which means they can’t handle the high heat you normally need a really hot iron in order to iron on the interfacing. If you want to add another layer, why not just have two layers of sheer fabric? When you sew your pockets and hems, you can just sew them together at these points. Now working with sheer is kind of a pain in the neck because they tend to slip around so getting two panels to line up perfectly while you’re trying to pin and sew them together might be tricky. You might want to pick up some spray basting at the fabric store. It’s like a spray temporary glue, that way you can stick them together to make it easier for you to treat each panel as one. good luck!