I'm getting a cheap 3 lb. sleeping bag ready to use as an UQ. I'll probably cut it down to about 40" wide x 60" long. What size shock cord will be right to hold it in place? I'm gonna run the shock cord length-wise through channels and attach to my hammock suspension as I've seen it done on various videos.

I want it to be strong enough to hold it in place, w/out overkill. I know the sleeping bag is heavier than some other UQ options.

What size cord do you think? 1/8", 3/16", 1/4"??