On the use of polygonal electronic fence

Hello, everyone. I want to test the use of polygonal electronic fence, but I haven’t found its instructions in Wikili. Can anyone tell me?
Thank you.
In addition, I would like to ask, my multi-rotor aircraft, in maintaining altitude and climbing performance is very good, but in high-speed descent is more sloshing, netizens told me that the low-speed motor thrust curve changes lead to PID control inappropriate reasons, how to solve this problem?

In addition, when the flying speed is over 10 m/s, the attitude wobble of 5-10 degrees will occur, which is also a problem.
To configure:
TM-U8lit, 80kV
2995 propeller
60A FOC Electronic Governor
Take-off weight 10 kg