Well what do you mean by co-teaching? That can take a lot of forms. Are you both teaching the class at the same time, or do you take half of the day and she takes the other half, or what? If possible, you might consider doing Whole Brain Teaching just for you, and she can do whatever other management she wants. WBT requires you to change your behavior a lot, but doesn't really require much change to the classroom itself (IMHO you don't really have to use the signs, but if you do don't take up much space), so depending on what "co-teaching" means, you could probably do it without her. After seeing you do it for a while, she might be more willing to sign on.
Another thing to consider is to sell it as a teaching technique rather than management. At first glance, WBT looks and sounds like simply a classroom management system, but to sell it to a veteran teacher you might need to point out how good it is pedagogically. Most of WBT is based on neurological research, and its most powerful strategies (such as Teach-OK) are designed not to control students (though they help with that), but to get them to learn better.
The bottom line is that WBT requires a lot of enthusiasm from the practitioner, and can't be forced on anyone or done reluctantly. I worked at a school where it looked like a year or two ago the principal had asked everyone to start Power Teaching, and for most teachers they were just using Class-Yes as a token gesture after a while. That said, most teachers get pretty excited about WBT once they see it done right in action.