String size

I've used the kits that I think we got from Camping World as well as redoing several with monofilament fishing line. I've found the fishing line works well since it is less prone to abrasion wear like string is and doesn't break as easily as a result. It also comes in various tensile strengths. Use the strongest you can find and you will have good results and probably never have another failure unless your knots don't hold.