Tough question and no easy answer at hand. NATO vs WP up to '60s (?) would probably be a division based WWII type of conflict. As you approach the 90's doctrine, weapons, optics, and intelligence favor brigade or equivalent task force operations (at least for major NATO nations). For wargaming purposes, as a starting point and trying to keep it simple (and possibly dumb) I'd group unit frontages in two groups (WWII and -say- modern). A "modern" reinforced (?) company covers a "WWII" battalion's front. So for a 200 hex height map (~8 km) and on the defense it would be something in the order of a "WWII" regiment or a "modern" battalion. On assaulting the same units would advance on 2 to 3 km front (50-70 hexes on the vertical).
For WWII unit frontages have a look at this:
http://www.balagan.org.uk/war/crossf.../frontages.htm
Again I want to stress tha this is a veeery rough and "order of magnitude" approach.