Just my opinion, but ALL BORESIGHTING TOOLS ARE BASICALLY MEANINGLESS.
Mount it. Look down the bore at a 25 yd target while it is on a solid rest. Adjust your scope to look the same. This should get you on paper. That is all bore sighting will do also, unless it doesn't like 70% of the time.
If your not on paper, ask an experienced shooter to do it or get a bigger target!!! . . .or go see the eye doctor.
Then fire 1 shot and adjust from the POA to POI. You should be ready to go to 50 or 100 yards at this point. . .
Oh yea, and I want the $17 - $60 the next time I do this for someone. The last time I did this for someone, they shot up my target stand once they could hit something!