Chas I really like Gold tips brass weights, that screw into the back of the alum. insert. They come in 10,20& 50 gr's. You do need there long allen wrench. It is run in the nock end of the arrow to screw the weights into the insert. (That is already thread to accept them.)
Most alum, inserts are not threaded all the way through. But that is nothing to fix with a 8-32 tap run though them. So the brass weights can be screwed into the back of the insert.
Makes weight tuning real easy, and or to increase FOC JMHO
They look like this