Charging in Napoleonic Wars

There have been several interesting discussions on the Ancient and Medieval Wargaming Group forum on Yahoo, where the rules in all of Neil Thomas' books are discussed. One poster recently pointed out that Neil's rule about charging is a replacement for the typical rules found in Horse & Musket rules where the charger checks morale to see if they close and then the defender checks to see if they stand. Neil's rules do away with that mechanic. I won't go over the entire discussion - join the group if you want to read it and other great discussions on Neil's rules - but what was interesting was the poster's comment that you can only charge smaller units than yourself. (Size being determined by the number of bases in the unit.) I had apparently read the rule wrong as smaller or equal to.

This presents some problems for my American War of Independence Wargaming (AWIW) rules as there are a lot of historical examples of smaller units charging equal or larger units. This leads me to ponder three points:

1. The number of men represented by a unit of Elite troops may be less than the number of men represented by a unit of Levy (Green, in AWIW) troops. So, a unit of four bases may represent 250 Guards (Elite troops) or 350 Regulars (Average troops), or 450 militia (Levy/Green troops).
2. The morale of the troop may need to come into play so that smaller Elite units can charge equal or larger units of lower quality.
3. There needs to be a special rule granted to the armies that historically consistently were able to charge despite being outnumbered.

Any of these methods, or some combination of them, might solve the problem of how the rules can reflect historical events. For example, I have studied the Battle of the Cowpens and am now studying the Battle of Guilford Courthouse and both are full of examples of smaller units charging larger units. Without using one or more of the considerations above, the British would not be able to charge the first line in Guilford Courthouse as the Patriot militia units were larger by far than the British units.