Last year I was fishing down the bank from these guys that were fishing for cats with a slip float setup. They were using these black nylon leaders by Eagle Claw with 5/0 hooks. I think they were Saltwater or something, not too sure. They dont have any snap swivels like some of those leaders, but have a barrel swivel that ties to the main line. Are these good to use for a quick change leader and do they hold big cats?