I use Berkley transition (it's gold out of the water). I find I can use 10lb test for all my lake fishing with this gimmicky fluorocarbon. It always breaks after a hundred fish or so. I just attach it to the mono with a simple cinch knot, but that's the only knot I've ever needed for leaders. Maybe some day I'll get more fancy with my knots, but I haven't seen a need for it yet.