Copter's GPS_GOOD_HDOP and radius geofence in Plane

Hi everybody,

I can’t find in the docs, could you please clarify the following problems:

-is there a parameter in Plane with a functionality similar to Copter’s GPS_GOOD_HDOP? Where to setup the HDOP threshold?

-is there a radius-defined geofence in Plane? Or one needs to draw the polygons for every location? (inconvenient and likely to cause problems). I would not expect the radius-based geofence to be very precise in sense that the aircraft would never leave it, triggering the RTL after crossing the “tin box” border would be perfect.

-from the docs about SERVO_AUTO_TRIM:

such that when flying in MANUAL mode, the plane will be in the same flying attitude as when flying in throttle controlled modes (AUTO, CRUISE,etc.) or FBWA.

where STABILIZE goes here? To MANUAL, to “throttle controlled modes or FBWA”, or is not relevant?