Step 1: Materials
The pair I used happened to by 72" long, but I had lots of extra string left over. Fifty inch laces should be plenty long. Alternatively, measure and cut two pieces of rope - one 30" and one 50" (one of the laces will have to be trimmed anyway). Stay away from polypropylene ropes or anything else that is too slick as this sling relies on friction for readjustments.