Indeed very few knots fail with 20# or 50# "tippet". In those strengths I'd have confidence in any legitimate knot.
I would say a more pertinent test would be say 4# monofilament and 12# or 15# flourocarbon which are probably the most common for freshwater trout and saltwater flyfishing.
I am trying to arrange actual testing of the lab variety. I might only be doing breakage tests at home but it's still a lot more than those who are posting are doing.
Now my curiosity is piqued, it will be fun.
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