". . . tying a double overhand knot in the very end of the tip end of the leader after the furling was complete. Doubled the leader over about a third of an inch and . . . "whip" the doubled over leader from the tip ring to the overhand knot."

I'm reading this to say the tip ring is captured within a Surgeon's Loop and the section of loop between the knot and the tippet ring secured with a 'Snell Knot' . . . ?

Yes . . . No . . . Maybe so ?

No matter, just so it works. (Did you try it from 'The Rock' yet . . . ?)