Your method does work for the most part. However, when I moved the adafruit sd/rtc shield to another board I had to send the time to it again. Should the rtc maintain the time once set since it has its own battery? It does maintain the time without moving the shield to another board and cutting power for a minute or two but not sure yet what would happen if we lost power for 15, 20, etc minutes.
definitely better than what we had before though so thank you!