The June/July issue of "Fly Fisherman" has an extensive article on comparing leader materials (Mono and Flo-carb). Some of the results were damned startling; as in who would guess? And not just between brands.
Seven different knots were used and at least seven passes so they could 'average' the results. Odd part was the 'heavier' the leader, generally, the lower the actual knot strength when done 'tippet too tippet' material for a tapered leader. A 50% loss was more often the case as 'knot.'
A straight run to the fly held up pretty darned well based on the 'X' of the material. But as noted above, you toss in a knot and you're down (on average) 50%!
That be true, just a question of how many 'steps down' you want to go through. Built my own leaders (and out to many friends here and in the UK), just a how long do you want it, off of what weight rod, bla-bla-bla.
They were really, as in really-really, good. So what? You could buy a RIO (lots of alternatives) that were just as good and 'just get on with it.' fae