(All views are if you were driving the front cart)
First Wave is 1 mob at the left front cart.
Second Wave is 1 mob at the right middle.
Third Wave is 2 mobs, get the center left first, then run between the carts and get the center right.
Fourth Wave is 2 mobs, after you push the rocks down, get the front left, then the front right.
Fifth Wave is 3 mobs, go left rear for 1, run behind the cart to the right side middle to get 2, then run between the carts to the left towards the front to get the final mob.
Sixth Wave is 3 mobs, get the front left first, then run to get the front right, then immediately behind that to the middle right for the last mob (Some people may find it easier to use the encounter circle for the last two).
Lastly, push the final rock down to spawn two mobs in front of you, use the encounter circle.