Connie Smith, part of the OAMC music team, does the "choral seating" of the first tenors in order to find the best blend of voices.
They sing a short vocal exercise, over and over again, in groups of two, three, four, and so on, as she walks in front of them and listens. Chorus members are switched around, individually or in groups, until the most satisfactory arrangement is found. The improvement is noticeable, even drastic at times, even when swapping just two adjacent members.
It just sounds right when she's done!