I've already tried that, they want me to pay them to do that 2.
The reason I was thinking about Parelli, is because he has the name, fame, and he advertises trainers on his site.
To really benefit from all these "natural" horse trainers promoting "their" system (which was around before they were born) you'd need to take instruction from them all, because everything they do is good and bad (but they'll never admit it) depending on the horse. No one system is good for every horse. The old timers knew that you learn the horse and train it based on what works, but that's not always the same for every horse. The majority of training a horse is common sense, learning the horse and patience. The rest is time and sweat.
I've loved showing people the two I'm training now as great examples of what works with one doesn't work with the other. Something as simple as teaching them to give me their feet and letting me hold them took 15 minutes with one and she'd give me all four feet. The other horse took a day for the front feet and almost two weeks before she'd pick up and let me clean the back feet. Of course 4 days of the 2 weeks was spent finding out things that weren't going to work and finding something that held promise and ultimately did work.
My point is that focus more on learning how to train and less on some system that someone is marketing. These marketers run into problems when they get a horse that doesn't want to learn using their technique. They are then stuck with having the force the situation (which is NOT teaching "naturally") or using a technique that's not part of their "system" (they can't afford to do that, because after all the hype they put out it's bad press to say "my system doesn't always work best for every horse in every situation")
Ok, I'll climb down off my soap box . I have to go trim 8 feet on this hot day