I spent a lot of today (more than I'd planned!) redoing my old, tiny type, very faded instructions for making those rope halters :-D Still need to collate the new text and drawings. Then I will get the pages copied onto a disk to make it easier to file AND to email. I checked out a few web pages on how to make these halters but they were pretty sketchy.
I will email it to all those who already asked; and any who prefer printed out pages (about 4) through postal mail, please send me a SASE as I did have a lot of requests. This halter has the fiador chin knot and I also included how to tie on the mecate (22' rope making a loop rein plus a long lead line) if you want to ride with it as if it were a hackamore. My donut-brained Ay-rab is as (un)controllable in this as he is with a snaffle anyway, so I always ride with this "rope hackamore" now and it's fun to see other horse owners' reactions... "Ohmigawd, you're only riding with a HALTER??"
Materials info is also included but if you want to go looking now, get 18' to 20' of 1/4" diameter double-braided polyester line aka "yachting braid", such as New England Ropes Sta-Set polyester line available from West Marine -- www.westmarine.com It's 49-79 cents a foot depending on color and type.