I usually just tie them approximately the same length as the tail. Sometimes shorter depending on the individual strand. If it's longer than the tail material, I cut it. I usually use a single strand of Krystal Flash or tinsel doubled over and cut, then doubled over again when I tie it in. That gives me two strands on each side. I have both Flashabou and Christmas tinsel. If I use the Christmas tinsel, I only use one strand since it's thicker and a little stiffer.