I have noticed that when I am using the outer side of my upper thigh as my sensor site, it takes such a long time for the sensor to stabilize and enter Auto-Mode for the Medtronic MiniMed 670G.
During my pump training, I was told that Medtronic now officially recognizes the outer side of the upper thigh as a good insertion site for the Guardian sensor. This was not the case for the enlite sensor.
However after stabilizing, from my experience, this site gives the some of the best and consistent sensor readings.
TIP: To shorten the time it will take the sensor to stabilize and enter Auto Mode, you can insert the new sensor and leave it in place a couple hours prior to replacing the current sensor.