Ruiz/Rubio look like the more structured, percentage pair, built around controlling the net and extending rallies, while Cepero/Torre typically bring higher variance with faster triggers and more risk on the volley/overhead. In Valencia P1 summer conditions, the team that manages tempo and lob quality usually wins; that slightly favors Ruiz/Rubio if they keep errors low. Prediction: Ruiz/Rubio in a tight match, decided by who holds the net longer and protects the backhand side under pressure.