I don't believe you can have more than 200 men per unit. Besides, numbers are simply representative in this game. No ones computer can handle 100,000 soldiers on the battlefield anyways, so being "historically accurate" really doesn't have any bearing on unit sizes. Plus, the actual numbers of soldiers that fought in the largest battles during the RTK era is still widely debated... certainly no more than 150,000 ever saw the field at a single time.
However, you can edit the numbers in the export_descr_unit file to increase unit sizes.
Each unit has a "soldier" entry where it details the soldier model used and the number of soldiers in the unit. Let's use the Huben unit as an example.
Code:
type Huben
dictionary Huben
category infantry
class heavy
voice_type Heavy
banner faction main_infantry
banner holy crusade
soldier huben, 48, 0, 1.2
The last line that I show is the "soldier" line I was speaking of above. In that line, the first number is 48, which is the amount of soldiers in the Huben unit. However, 48 is the number of soldiers on the smallest unit settings. To find what it as at the highest unit setting, you multiply that number by 2.5; so 48 * 2.5 = 120 soldiers in a Huben unit at the highest setting. To get 200 soldiers per unit, you would need to change a unit's entry in the soldier line to 80. So if you want the Huben unit to have 200 soldiers on the highest setting, the soldier line would look like this:
Code:
soldier huben, 80, 0, 1.2
However, I highly suggest you be careful when messing with the EDU file, as you can mess up unit and economic balance if you make every unit so large, as well as possibly cause errors and CTDs if you don't know what you're doing.