Particularly good are the Stevensons' 'Accounts' of each lighthouse build which they had to write for the Commissioners. These are available online to read, for example Alan Stevenson's '
Account of the Skerryvore Lighthouse' prepared for the Commissioners of the Northern Lighthouses. It is this lighthouse that he describes as having granite stones that took between 55 and 320 man hours to dress
each, depending on their location and complexity.