I've never had use for a leader when fishing for whisker fish.
I slide a sliding sinker on the line, followed by a couple beads, tie snap swivel to line, attatch hook of choice. Only one knot to tie and potentially fail then.
If you're looking for big cats, then you should be fishing with live green sunfish- the big Flatheads love 'em. Make sure to only catch live bait from the waters you are fishing, as transporting from one body of water to another is a no no in order to help control the spread of VHS disease.
Good luck and tight lines!