A chair rail looks best when it is at the height where it can do its job: keep chairs from marking the walls. Your chairs don't get higher just because you have a high ceiling.

The question is chair rail OR higher wainscot/panel. I would say higher wainscot if you have the budget, as high as you want. It's already a dramatic room. Chair rail is 36", higher than that I think it's not chair rail anymore. But, 36" isn't wrong in that room, will still look fine. In fact 48" might look funny, without wainscot, because again it's supposed to be 36 from floor regardless of ceiling. And, you could do wainscot under 36 chair rail too and would look great.

Thanks for that comment and your absolutely right, the room is 15 feet wide, so the chairs have never actually ever gotten close to the walls, in the alcove seen in photo 1 their is an antique hutch that goes in there. The point being is that the chair rails do not really serve a purpose, and are more for design than anything, this is why I question should it be changed into chair railing....