Those are good links because I think you need a bottle jug knot and a fiador knot, check out this pic...
Buckaroo Leather Horse Tack, Use, Care and Maintenance: Fiador Throat Latch-a Vaquero Tradition
But I was trying to find instructions on the length of cord and how to tie them all to make the whole fiador setup. Does that make sense?
Or you could bypass the whole fiador idea and use a throatlatch if you were in a hurry to something built until we figure it out LOL!