I recommend alternating between group recitations that focus on choral harmony and listening comprehension, and individual lessons to review sightsinging and keyboard material. I believe that the benefits of ten critical minutes of private keyboard instruction outweigh whatever is to be gained by practicing piano in a group:

• Private lessons give you an easy way to gauge student progress. Students have less chance of falling through the cracks if they are forced to prepare ten minutes of material every couple weeks.
• Keyboard skills tend to vary more dramatically than singing skills; individual lessons make it easier to choose appropriate material for each student. (See tips for designing keyboard material for different levels. [TO DO: Add link] )
• The H&C lectures I taught last year already involved a lot of group singing, so Mike G. decided to turn all recitations into individual 10-minute meetings.

Group keyboard lessons using one piano are an important part of the Walden School musicianship program. [TO DO: add link] I tried to use the Walden keyboard method as a TA, but found that weekly meetings were too sparse to establish the foundation we needed for successful group drilling.

---Ness