Melee is resolved using individual combats as per the original Charge! rules. This is a point of importance to me, as the procedure generates some excitement (as well as occasional bad language and unkind remarks). But Charge! uses a single dice throw for each side, with multipliers according to the number and type of figures. With the variant rules, each side uses a 'score' which is calculated as the sum of the melee values of the figures involved plus the value of a dice roll.
The melee values we used in our Napoleonic battles were:
Heavy Cavalry = 3
Light Cavalry = 2
Infantry = 1
So if two light cavalry troopers are fighting one heavy cavalryman we'd be comparing (2+2+Dice) vs (3+Dice). A casualty would be removed if a difference of two or more in scores result (as the ordinary Charge! rules dictate), although an additional saving throw of 6 on a single dice roll is allowed for cuirassiers.
It should be noted here that infantry are decidedly weaker in melee than before; no less than three of them are needed for an equal combat against a single heavy cavalryman. I believe this to be a considerable advantage over the original rules where infantry, if they have significantly narrower bases, can rather too easily mob cavalry. As John Preece has noted: allowing only one infantryman to fight any given cavalry trooper can be a useful amendment to the original Charge! rules.
Dragoons Versus Cuirassiers