I opened this thread to get info about WWVB, but as part of my main question about calibrating the Aging register of the DS3231. Since I've settled on using GPS for this instead of WWVB, I've returned to the original thread to follow up with GPS, and post my software:
https://forum.arduino.cc/t/ds3231-setting-aging-register-to-optimum-value/1112826/13