Here you can set the AIs building Priority, the AI will always build drop off buildings for the 2 main resources first to avoid not having enough resources to construct these buildings. After this the AI will follow the building priority. This node is found in the BP_Masterblueprint.

The variable Max Towers Per Building controls the number of defence buildings that the AI will build around its non combat building. Note this node is found in the BP_MasterUnit blueprint event graph.