I'm not sure you can cut a piece out of the skirt and fuse it without making it look sloppy. What kind of material is it? Is there enough material at the ends to trim 3/8" off of each side to attain the dimension required? How does the skirt attach, with clips or velcro fasteners? What is the shape of the panel? Is it a frame with a recessed panel? Give us a little more info and we might be able to figure something out.