It will certainly stop under any condition so you should be safe to try it in a high wind and see at what power it furls. If you think it is too high then you can just shut it down and reduce the tail weight when the weather is suitable.

You will probably find that it produces maximum power when the tail is at about 45 deg. Most of these type machines tend to reduce power in even higher winds so if it doesn't exceed 1500W you should be fine.

If you want to include some control scheme with a small resistor attached to a temperature sensor you could infer stator temperature from the temperature rise of that resistor.

You could perhaps decide that if the current was above say 60A for a period of say 20 mins then you would shut down until the wind dropped. By this time your batteries would probably be fully charged and you would be diverting load.

If proportioned correctly and with the same time constant as the stator the little series resistor would follow stator temperature. It would not be exact unless you measured true stator temperature and calibrated it, but even if you guessed at the operating point, the temperature rise with current squared would be so quick that you would have a good idea of overload. Perhaps you could just measure the shunt temperature and use that rather than using another series resistor.

You could combine this with overspeed protection which you could easily sense from excess ac volts or even measure frequency.

In any of the fault modes you detected you would then shut down, not try any form of loading.

If you have copied Dan then the furling should be near, but you may have some variation due to different tail materials and weight. Just check it in a good wind and adjust if you feel uncomfortable with the maximum output.