How many makes too many?

Group wordsmithing is unpleasant.  Trying to edit a document or draft a statement are tasks for one person or small groups of two to three.  This may seem obvious.  But how do we go about making decisions for what is best to decide in a large group meeting, and when it is best to send to a subcommittee?  I usually tend to believe that smaller groups who volunteer for the job, have the confidence of the larger group, and are charged with developing a recommendation can get work done in a more efficient manner than in a large meeting setting.