"Vanish" is particularly weak once knotted; assume it to losealmost half its strength. Test each rig with a spring balance, and if it will pull half its quoted b.s., use it, but only as being three pound b.s. (in this case).
I'd try another brand, but test it first, and test real rigs - all fluorocarbons seem to hate being bent through the hook's eye (as in knotless knot rigs) and part a bit above the hook - and believe your scales, not the label!