Castelló/Rufo should enter as the more stable, higher-ceiling pair for a Buenos Aires P1: better in structured rallies, more reliable transitions, and stronger point construction under pressure. Rodríguez/Canovas can compete if they speed up exchanges and drag the match into chaotic defending-to-countering patterns, but over three sets the favorites’ consistency at net usually wins. Prediction: Castelló/Rufo in 2 tight sets or 3 if the ball stays slow and defensive.