So far, I haven’t found any reports on the decision to expand the church – or for that matter plans for the 75th anniversary – before April 18, 1939.
I haven’t found any reports or updates on construction between the application for the permit on June 11, 1939 and the first use of the chapel on March 17, 1940. Finding some information on construction might illuminate why the cornerstone was put into place at the end of the project rather than at the beginning.
Other than knowing it happened on March 24, 1940, I haven’t found out anything else. Presumably it took place in connection with the 75th anniversary celebration?