We sit and discuss, talk theory like some sort of scientific PhD about line weights and densities as if we have cracked the code.
When in actual fact at this time next year we will arrive at the river with some sort of different theory and set-up, everchanging and evolving our thought process on how to catch fish. Just as our ancestors probably did 1000s of years ago, the constant battle between man and beast will continue as long as we both exist.
However, that being said line setup is just as important as the rod, It allows you to fish the depth that you desire and allows the rod to cast as it should. Paired with the right line setup each rod should excel.
The + mark on our rods dictates the lightest line weight we feel works and then it's up to the individual to find out what they like from there to the fishing experience they want.
We feel lines are important, you wouldn't play golf with one club so bring all the lines for all the different situations that fishing can bring your way.
We Don't Know..........