For me its not the actual gait that a horse needs to carry. They just need to get the message. For me, in my head, it goes from "Go" to "Go Away" to "GO AWAY NOW AND FAST". If I tell them to go away now and fast and they just amble away, Ill make my presence bigger by waving my hands and broadening my shoulders.
Sometimes the signals are there they are just so subtle, you can't tell. For a horse that has been abused for him to drop his head 2 inches is a head drop to me. Its a start. Monty has been using his method since dinosaurs roamed the earth. He is an expert. If it takes a while to get a good join up, then it takes a while.
As far as the not chewing thing, be positive that he is not. Some arent outward chewers. They just kind of lightly grind the teeth. Ofcourse you want him to be licking and chewing like a mad man. Some just dont.
Nico would never come to me. I tried the arcs but he just wasnt getting it. Instead, I pick his opposite direction in the round pen, keep my eyes down and my body soft. I walk the rail slowly. One step at a time. He usually will follow and then touch me.
Of all the NH stuff, Montys makes the most sense to me. Always did like him.