Cherumbic, what ever you were looking at wasnt a passoa then. the horse can bend properly through the circle as there is equal pressure on each side (unless you have ajusted it incorrectly)
You want equal pressure on the mouth because you should not use a bit to create bend bend should come from your leg!
You would also have a lot more control if you used a lunge cavesson so that you are leading from the front of the nose and not from wherever you are lungeing from. I suspect it was from the bit which is not good.
Finally, when he gets into a running panic run him into the fence so that you block him as he heads straight to it. means you have to move fast but it works!
With this horse you would have far less control in a cavesson. Lunging from the bit gives you far better finess in signaling the horse, cavessons are fine for a normal horse but not for problem horses. I have always lunged from the bit and most top trainers I know lunge from the bit as well.
We have tried running him into the fence, he went through the fence doing damage to himself and the fence! This horse is a horse many proffessionals concider rank and have told me to have shot.
He bolted because he had known nothing but pain whilst being worked. He is a true rescue case who has been so badly abused that he had a fractured pelvis, he was not castrated by a vet and he paniced and ran blind with any form of line anywhere near him.
So please stop trying to tell me how to work with this horse when believe me we have tried everything with him and this is what works. I have had TOP trainers working with this horse, we started with a top producer who told me to have him shot, we then went to a NH person who wafted a stick at him and backed off when he flipped out, then I took him to melanie watson she is the best in the UK for problem horses and does not come cheap she got him ridden and hacking out but always said he had a problem, weve had him investigated by vets spent over £5k in vets fees alone, found the fractured pelvis and both my vet and melanie suggested a passoa when we brought him back into work. I currently have a rideable pony who has stopped bolting, is beautifully balanced when I'm riding him and is very happy to stretch into a contact.
The passoa works