I imagine that if these same folks were to assemble anew, we could save some time by repeating the same songs. BTW they did "let go and have a good time.". They were able to do just that because we sang songs they knew and only occasionally introduced a song they didn't. It is for the new material that my suggestions are most important. I make it easier than easy to learn a song. I sing their part and then we sing it together and then we sing it again. While we are singing, I call words, just as a little reminder. I promise that everyone gets it and sounds good doing it. I stand near the less experienced singers to give them encouragement and a strong voice to follow. When we do any blending or harmony, I let them know how lovely it sounds to me. I share their joy and, what's more, I really mean it.