Thanks for your observations Audrey......

As far as selecting the correct key for singers is concerned, I don't think it is possible to just state a preferred key for a 'singer', irrespective of the song.

It must surely be determined by the range of notes within the song - i.e. from the lowest note to the highest note and this will vary considerably, for different vocalists. Some have a wide range within which they can sing comfortably, without straining their voice, while others can have a more restricted range and a particular song may have to be 'key-shifted' to keep them in their comfort zone. Not only that, but there will often be differences in suitable keys for a particular song, depending on whether the singer is male or female!!

When I had a small group several years ago, we had a male singer who had a great voice but his actual vocal range was fairly restricted and he could not sing quite a few numbers in 'copy' key. One of his favourite songs was 'Whiter Shade of Pale' whose 'copy' key is C (A minor) but he just could not reach that high note in the chorus without straining (...and so it WAS ...) so it had to be dropped to Bb.

The reason for my original request relating to the Christmas songs, is that I've never played them as accompaniment for singing, so I had no idea as to the generally accepted key, which would be OK for most people's range. I didn't want people 'singing in their boots' or muttering '...he's playing that too high....'