I just tried cutting one down! If you cut the insert on the very last indention, you'll have an insert that weights 68 grains... This is almost perfect. I was trying to get one 67 grains because the aluminum insert that comes with the shaft weights 17 grains. I wanted to add 50 grains to the 125 grain judo/ fieltips/ small game heads I had, so I'm only one grain short....
When I say cut it at the last indention, I mean the last one away from the front, where the tip screws into it...