Well he currently has strong muscles along his mane line and the underside of his neck is strong (probably from resisting contact) but he has a dip in his neck where the neck meets the shoulder area.
I am interested in using a lunging system to help solve some of these problems. Possibly a pessoa system. I would like to hear your thoughts on the pessoa system, whether you like it/use it, and if not what you use instead? Is a surcingle/side reins better?
Also what are other exercises that I can do to help him stretch his neck?