Not sure if you already answered this previously but is there a chance you could use Robert's upper body instead of vanilla?
All that would be need to change is so the horse part lines up with the torso of robert's. So it should be no problem.

Great looking mod so far! :ahhh: :tops:

If you have any ideas.....Im open to hearing them. But I cant think of any way to replace them. It just falls into the same area as sneak, centuars are just not agilie enough and too big to do these things.
Ravin
While I could script it, this would require heaps of key detection, and would make this totally player only. I want to aviod that, I really want is possible to make NPCs from this. Then again, they might ot if different ot how i think they do.