Okay, a little Theorem et Practicum here:
Marv - You are working with the 130# I gave you. You are using the same BASIC principle to make the loop that is used to splice eyes into double braid nylon mooring or dock line, as well as the application of the Chinese finger puzzle theory to line/loop connection.
If you "suspect" your ability to make a multipass loop (many times through side to side, ending with BOTH sleeves over the fly line because you threaded the bitter end back into the throat of the standing part),
take a piece of hollow braided polypropylene line - the cheap yellow plastic stuff and recreate what I just said above -
there is NO WAY you can finish hollow braid Poly line without dying the end off INSIDE the braid. Then, the outer sleeve will slide and expand and allow you to move the inner "finger" farther in or back out of the "puzzle". There's the picture.
Apply the picture to co-ordinate with the two ends of the 130#. Slide the outer sleeve down and out of the way, whip the inner sleeve to the line, and then cover and whip the outer at the same point. All you have to do to keep the loop the same size is fit it over some kind of mandrel so you don't have to pick it out...is that clear enough ro does the picture make sense? - if not I'll show you this weekend. In the meanwhile, see if your wife has any crochet hooks smal enough to pass through the 130#.