Okay, I've drawn a scale model of the wall... I realized two things.. 1. I was forgetting that I am planning on putting a wall paper border at the top of the room (this helps even the perspective) and 2. that I can go with a wider chair rail to match the border and the existing baseboard. Now, am I correct in figuring the historic chair rail height is 36" on center? If that is the case, then I think the proportions will be fine. And we have the taller chairs for our table anyways, so that will work.