[@Karos] If you read the post two above your own, he says:
"Platoons are anywhere between 15-ish to 40-ish irl but I might hard cap it at around 30." 
You can ask him for special dispensation to have more or fewer soldiers; I have 70 soldiers, but considering that each of my soldiers is less than 6 inches tall and not particularly strong, I don't get much of an advantage.