It doesn't matter which direction you go, either toward low stretch Kevlar and other high strength fiber or toward high stretch nylon you always need the same size fishing reel to bring in a certain size fish. Length X CS area of the line is constant regardless of the material.
It would be interesting to know if there was an actual correlation or law to back this up. Maybe there is more to the units of toughness [energy] that what is generally known, or, at least what I know.
Bret Cahill