I'd like to know if there's a way to set a default/home altitude to which the barometer is set at the beginning of every new activity recording.
Also I don't clearly understand how the automatic barometer calibration works.
Automatic adjusts the elevation eventually (you will get a elevation jump in charts).
There is no other possibility to set elevation in the device.
Personally, I added elevation support to Trails plugin to fix this at import. AfterImport plugin also fixes this.
I also want to know if the device records temperature during the activity and how it can be retrieved.
Not included in the device accessible information so I assume it is not recorded.