Why does Clinton Anderson and Pat Parelli use rope halters for their training?
Clinton Anderson uses a halter with four knots .. two knots over the nose for "more bite".... I don't use these types, I don't think it's necessary, haven't had the need to and I've retrained bolting and rearing and all that with a regular halter (flat web) and a rope halter that just has the two knots on the sides (which really don't do much except hold the halter together)
I use the halter that's more like Parelli's. Plain and simple.
Also why does people use them for lunging?
Why not? The horse doesn't care what you use, he cares about how you use it. I lunge horses all the time with rope halters and it works out great. I do the "lunging for respect" that CA does....sending (shoulder moves away) and stopping (by way of disengaging the hip). You can teach roll backs and all the gaits and teach a horse not to pull againt you (hip disengagements are the key)
You can get a horse so light that he doesn't pull....he keeps his nose tipped in toward you and moves accordingly with just a simple light opening or closing of your hand on the lead rope.
Last question... always a mystery...
How do you adjust the knots and where are they suppost to go to fit properly?
The knots aren't supposed to be pressure points. Simply adjust the halter so the nose part doesn't block the airway and the halter fits properly behind the jaw, not hanging too loose. That's it.
I like rope halters because they are handy. They're light. You can leave em under the bridle for tying or leading him if you need to keep the bridle on.
I have trained using the web halters (flat) and you can get the same result, but just like anything, a little help (lighter and more direct contact...in other words,...the horse has nothing to lean against) with the rope halter does give you an edge....but again, it's not necessary. But it is nice.