Ask Mark Waddington, because he raised this exact question a few months back. The "soft fishing line" Is beading elastic, and much stronger than standard Bands It also doesnt perish. Mark will be able to help you with the size needed, and exactly how to thread it.
Tell him i sent you.

you're like Yoda.you dont say much, but what you do say is worth listening to....
Greg Wilson about.... Me.