For each year:
- Sum the word counts.
- Divide the sum by 301, the number of days in 43 weeks.
This provides the target average lesson length for that year.
- Divide the number of words in each book, by the target average lesson length.
This provides the preliminary figure of the number of days for each book.
- Round those quotients to the nearest integer, and adjust the target average lesson length up or down until the total number of days is 301.
As of 09/06/20, this has been finished as to Year 1, Year 2 and Lent, and is in progress as to Year 3. The current status of the work appears in the file, "Allotment of days to books," under "Resources," here.