What is the best way to defeat the castles on invasion 3

This is how I always do it on all of these i put them in order of when to deploy them. I also put how much gold you get.
level 1: 10 archers and 1 cannon-4000
level 2: 30 archers and 1 cannon- 6000
level 3: 50 archers and 1 cannon-8000
level 4: 70 archers and 1 cannon-10000
level 5: 90 archers and 1 cannon-12000
level 6: 110 archers and 1 cannon-14000
and basically you keep going like this: buy archers until your money drops to 1000 then buy a cannon.