A chief pilot I once worked for had a simple philosophy when selecting check and training captains. Those who pushed their case never got a look-in because he surmised that they were on some sort of ego trip or power trip. If they demonstrated nervousness in bad weather or got rattled when the first officer screwed up they were forever banished to line flying only. He selected trainers by flying with them and going for the quiet achievers who demonstrated above average handling skills and a willingness to give first officers flying when conditions were difficult. From the results and feedback obtained from their trainees he then selected checkies.