AutoTuning a Glider -- power on or off?

I am working on bringing up a PixFalcon running ArduPlane latest FW. Aircraft will be a 2M or larger e-glider, with soaring and thermaling being the primary focus. Still in bench-testing mode, but looking forward to maiden soon. As I read up on flight modes and auto-tuning, I wondered if I should fly the AutoTune routine power on or power off. I had initially assumed power on, but as I read more about it, it occurred to me that perhaps running AutoTune power off (i.e., gliding) is better. Or perhaps there would be little difference in the results between the two methods. Welcome any input.

Kelly