Near the bottom of this page on the Super Ikonta III and IV, Jurgen says, "Before loading your film, cut 2” of film paper backing from an old film and tape it to your new film’s leader. You’ll have to experiment, you may need 2 1/2” or 3” … depends on your camera of leader."

http://www.certo6.com/cameras/zeiss-super-ikonta

He's also got a couple of pictures off to the side.