Not a bad question from a dogs supporter Cant say much on that subject, my boys never even made the finals. I did think they had a passport for bulldogs supporters to come up the range but I may be wrong
As far as I know it is the recomended line rating of the rod, so if its 3-6lb they recomend using 3-6lb line on it.
I use heavier than recomended on my Barra rods, but I back the drag off a bit to compensate. I mainly use the heavier line for abrasion resistance.
Cheers
Steve