I wholly agree with SonofMartin.......... "Tie on and cut back, until the fly rolls out...........".
Personally, I've stopped using furled leaders, due to weight and fighting the algae build up they can cause. (On still water, of course, not so much on moving). Instead, for even better effect, roll and presentation, I've started using the "Ploy-Pro" shooting, one piece, fore-leaders. Same theory. more or less, but with silk smooth finish and no weave or furl to catch up on micro-debris. They come in various lengths, to which you merely use a loop to loop, for your final tippet choice. They're "coated" in a soft poly, which makes them turn over ten times easier than a furled leader ever will.
In fact, try this................take a furled leader, a regular leader and a Poly Pro, tie on your favorite tippet....... a fly, then actually cast the leaders.... BEFORE attaching to a fly line! You can actually cast a Poly Pro, yes, it'll turn your fly over which isn't easily done with the other leaders!?! No, I don't sell them, I just really really like these new leaders and after 28 years of throwing the long rod, I've pretty well "tried 'em all"!!