Sometimes it’s hard to use the 311 rule because the congregation changes so much from week to week.  I would still use the 311 rule but watch the members of the congregation that are there on a regular basis, select a variety of people so that you can get a true reflection of how well the song is being received.

The other thing that I would do in the above situation is to re-teach the song (Nothing heavy just sing a verse and chorus to them).  I was once in a church where I had to re-teach songs nearly every week, I prefer to re-teach and drop other songs rather than lose half the congregation because they don’t know the song.