I got my "butterfly" field carriage pretty much finished just before major shoulder surgery Tursday, June 23, last week. One of my last acts was drilling the touch hole to make it operational instead of it being a large, heavy lawn ornament. I have all the accoutrements to shoot it, but the sponge head needs the wool cover. Where can I purchase some authentic lamb's wool to become the sponge cover? AND, once I have it, what is the proper way to attach it to the head?