@mjs513 The SPI mode difference is just since you're looking at https://github.com/adafruit/Adafruit_MAX31865 rather than https://github.com/adafruit/Adafruit-MAX31855-library ;-)
(The MAX31865 is for PT100 sensors, whereas MAX31855 is for Thermocouples)
(The MAX31865 is for PT100 sensors, whereas MAX31855 is for Thermocouples)