The motorcycle's throttle holder was made of plastic, screwed in the cable fittings, and when the nuts were tightened, the metal fittings came out, so a helical insert was required.
I used # 2, but it bent and failed.
It seems that # 2 does not work if taps are set in advance.
I used # 3 from the beginning and it worked as if nothing had happened.
There seems to be various procedures on a case by case basis.