View Volley
Volley and Bayonet is a grand-tactical set of rules.
Each 3 inch wide stand represents about 2-3,000 infantry, 1,000-1,500 cavalry, 12 guns (guns are on 1.5 inch stands). One inch equals 100 yards and each turn is an hour. Regardless of how many figures per stand, each unit has x number of strength points, representing how many hits the unit takes before being removed as combat ineffective. A fairly simple combat system; roll x dice per stand usually looking for sixes to hit the enemy with more nuance than is obvious on first read of the rules. A fairly generous movement allowance allows units to actually cover ground at realistc speeds if unopposed - something rare in games. This is the game to play if you want to do the whole battle of Waterloo rather than a part of it. The combat system has quite a lot of flavor. The command & control system is rudimentary. For one player per side you might want to add some more friction, since everything within command radius of the abundant division and corps HQs gets to move.
Some have complained that this is more like a board game, since battalion formations and lower level combat are abstracted into brigade morale and combat die rolls. Perhaps, but if you want to play whole, large battles in an evening this will do it.
As for stand size: 3 inch is full size, but many play at 2/3 scale - 2 inch stands (I do), 1/2 scale - 1.5 inch stands - and centimeter scale - 30mm wide stands. It depends on how big your table (and wallet) is.