Not saying you will never catch a fish on the back side of a wing dam, just you will catch more on the front side. Generally fish sitting on the back side are neutral, not looking to feed. Fish on the front are in ambush mode looking for a meal.
You can certainly troll the front/tops. It’s a great way to learn how each one is laid out. But once you got that figured out, you may find yourself anchoring on high percentage spots. You figure these spot out over time and base those decisions on water flow, temp, clarity and so on.
Cranks are a great search weapon and you usually pick off the more aggressive fish in that area. You may find that you can pull into a spot, pop 2-3 fish on cranks then change to plastics or meat to get another few of the less aggressive fish. All from the same anchor position.
-J.