In GBN rules each figure equates to about 100 to 125 men, or 80 to 100 cavalry. A battery of guns is rated as 3 or 4 guns per stand. So a battery is usually made up of two stands.
GBN rules is bases its maneuver elements on the infantry and cavalry regiment and the battery. So basically, a unit of 4 stands equals about 1500 to 1900 infantry and 500 t0 800 cavalry for 4 stands. there are also infantry and cavalry skirmish screens available for regiments as well as actual light infantry "battalion" screens, 8 figures....
To get more information on the rules and its mechanics go to "Grand Battles Napoleons" web sight. siegeworksstudios.com. You can download an example of play and numerous charts and other interesting information.
Also, pictured is the Duke of Brunswick's "Black Legion" of 1809 with the "Hessian Legion included... I still need to paint up a Austrian Landwehr regiment to complete the corps.