I am using a 6 weight and I usually use a 5x leader. My impression was that the strong leaders are beter suited to heavier flies. I am trying to catch a 25LB carp, and I know it can be done with a 5x leader, but it is the US record koi and i would rather not loose it. What is the heaviest leader I can use? I am casting tiny corn flies and stealth is key.