In my opinion, the most important element of the triad is firmitatis because each of the orders rely on some sort of stability in order to remain as strong structures throughout time. The second most important element is utilitatis because each of the orders are differentiated by what their purpose is, so the practicality of the columns is a major requirement. The final most important element is venustatis because the beauty of the columns is mainly emphasized only in the Corinthian and composite orders.