My experience with flourocarbon 'fishing lines' versus flourocarbon tippet is that the 'fishing lines' are equal to or a bit thicker than the equivalent regular mono. Tippet material seems to be the opposite. My Rio Flouroflex 5x is 5.5 pound breaking strength (actually breaks at right at 6 pounds on my scale) and is thinner than 4 pound Vanish (which breaks at 6 pounds too).

One thing I do know is that lines like Big Game and Stren are underrated on purpose. 10 pound Big Game breaks very close to 17 pounds (on my scale) and 10 pound Stren breaks at 15 or more. Apparently if you put 17 pound line in a 10 pound box, your line is stronger than the competition's?

All of this seems moot to me where flourocarbon is concerned. I use Vanish in 4 pound, Transition in 6, and a Cabela's house brand in 8. This isn't due to any type of preference, but rather just what I have on hand. All work just fine, and since these lines are supposed to be invisible, the way I choose them has more to do with fly action and size than breaking strength. Haven't had any trouble with even the bigger trout and pike breaking me off this past summer.

I used the last of my Rio Flouroflex 5x 100 meter spool a couple of weeks ago. I won't replace it, as I find no difference in catch rate from the less expensive lines.

And, as far as knots go, I've found that the Palomar knot is the strongest for my style of fishing. A nice combination of strength and ease of tying. I use it for fly to tippet, dropper line to hook, and attaching level leaders to the loop at the end of my sinking lines. Works great with flourocarbon.

Good Luck!

Buddy