Wainscoting height by the rule of thirds — 8, 9, and 10-ft ceilings, and the avoid-at-half rule

What this diagram shows

Three wall columns for 8-, 9-, and 10-foot ceilings, each showing where the wainscot cap should land. A green line marks about one third of the wall height — 32 inches on an 8-ft ceiling, 36 inches at 9 ft, and 40 inches at 10 ft — which is the rule of thirds. A red dashed line marks the exact half-wall height with an "avoid" mark, because placing the rail at exactly half the wall reads static and choppy. The wainscot band with battens is drawn from the floor up to the one-third line, and the height scales up with the ceiling.