Mine has been taped back together with Gorilla Tape so it might not be the original size. It's now 16 inches wide by 14 inches long. It seems to cover and work well.
I have just gotten my TC 22 back into service and had to repair the shield just last week. The former owner had kept the machine going by removing the skirt and covering both sides with a layer of Gorilla tape. Most of it seems to be in good shape with the only only one failure point ,where the skirt was taped to the L shaped mounting bracket. In a hurry I pop riveted two flat pieces of aluminum as a makeshift hinge point and started running her
I did find that you can order the piece from a company so if you want I'll find the info for you.. I have no idea how much they want as they have an "Ask for Quote" form on the website.