Here is a game i did with a friend. The challenge was to beat the AI faster than the other one.
https://www.warzone.com/MultiPlayer?GameID=15908792And you see how i attack and he does. He does it with large stacks focusing only a few enemy bonuses while i through out the whole game only attack with 2, 3, 4, 5's and having no trouble defending the bonuses from him taking them. You notice turn 4 how i have a border with both of the AI's bonuses of 9. I have 3 units infront of them and only place 2 on them to attack the bonus. Why do i do that? I know the AI is pretty incompetent in defending bonuses and managed to kill the enemy bonus with only deploying 2 units to my originally stack. And thats what i did everywhere. Attacking with very low stacks everywhere.