Here's a link if you want to increase your troop number per unit. But becareful not to set it too high.
Link
800 men per unit = serious lag when it all kicks off. 400 per unit has less lag. I wonder what kind of set up you would need to have a massive battle. 1200 men per unit = a possible 24000 infantry on one side alone. An equal battle would be nearly 50000 troops on the battlefield. Insane.