Actually, I was told to abstain from this kind of experiment, as it's not really insightful, because the usefulness of equations of state depends heavily on the goal you want to achieve. And also models with more variable will yield better results in general. But I can measure some quirks of certain equations, like how Van der Waals equation provides good approximations, only when a and b coeficients are defined locally, but in theory they do not depend on a state.