If you meani was able to unlock the missing piece in the equation, the diminishing returns of buildings.
some people might have unlocked the formula already, but i'm proud to say that i was able to unlock it myself.
BaseEffect * BuildingsPercent * BuildingEffectiveness * (1 -BuildingsPercent)?
Training Grounds
Offensive Military Effectiveness increased by = 1.5 * (TrainingGrounds / Land) * BuildingEffectiveness * (1 - (Training Grounds / Land))
Thats been knocking around for years ;p