I use 6 Artys, 30 Black Watches, 3 Supply Trains, 20 Fusiliers, 1 Biplane Mk1, and 5 Sabotage. I'm currently researching Shock Infantry. Don't worry about using anything tanky, likes (obviously) tanks or HTs, and ignore the factory. If the infantry doesn't work out well, replace with plenty of MGs, as they're cheap and can soak the splash damage. In GA, using 1 HT to soak the silo's dmg will be acceptable.