As far as determining how many Infantry brigades vs Artillery and Cavalry when making up your Army I have come up with a formula that I use. Wether it's 8, 12, or 15 brigades use this formula. Infantry = .6, Artillery= .2, Cavalry= .16, and Skirmisher= .04. This is your multiplier. So if you have let's say 12 brigades and your wondering how many Infantry just simply multiply by .6 for your answer of 7.2. Rounded down 7 brigades of infantry. The Cavalry and Skirmisher numbers can be skewed to your liking but I never go heavy with Skirmishers as I detach them when I need them usually. Have fun!