Tape the height out and see what it looks like to you....I always like 2/5 to 3/5 split. Persoanlly I love a low wainscoting, like 1/5 wainscoting to 4/5 wall.

Wainscoting alone does not affect ceiling height perception.

You decorate around the wainscot, so choose wisely.

Do a google search for "rooms with high wainscoting." In several of them you'll see art work and other decor placed above the wainscoting. I like how some of them look and think it tends to pull the eye up. Seems it might be a better option in rooms with low ceilings. I'd post some photos but my computer's not behaving.

Why do you ask?

I don't really understand wainscotting at all in anything but a historical (say, 19th c.) home. But if you like the classic formality, go for it. Here are a few examples with high panelling...

Modern Dining Room · More Info

Fair Winds · More Info

Hamptons, NY I · More Info

Ramblewood · More Info

Jeremy Kohm Photography/Palmerston Design Consultants · More Info

Here's a couple of the more common low wainscotting...

Attention to details · More Info

Oasis Architecture - work in Montclair and Upper Montclair NJ · More Info

Double Staging: 15XX South Street · More Info