In terms of the sources used, I sometimes used the original from the Musical Museum, and other times based the melodies on modern versions, eg. Ae Fond Kiss.

For Auld Lang Syne, I place both versions next to each other for reasons of comparison.

I terms of singing, some were originally pitched very high, so I chose keys for my book that would suit most singers.

This may be because in the 1700s-1800s, there was no standard pitch and instruments tuned a tone or so lower.