I have now padded the wire armature with strips of wool felt that I wrapped around the wires and stitched in place. I chose wool felt so that the wool fiber that I will felt with will stick to the armature. As I worked on the padding it occurred to me that it would be easier to just wrap the wire with thick wool yarn and tie the ends. Presumably, the wool fiber would needle felt to the wool yarn just fine. I’ll have to try that and see how it works. Another advantage might be that wool yard would be easier to find than wool felt.