Bingo, first Robin Hood and all that work down the drain.

Also, you probably want to make them out of tungsten, for its density.
2nd choice is brass. I made one for a guy years ago, to replace a lost
one from a set he loved. matched it for weight and rough end to end
balance. I don't think it was pure tungsten, but I honestly can't remember

Actually, having seen many,many darts that suffered the "Robin Hood"
effect, I think the problem is that the flight holder ends are cut
perpendicular to the shaft axis, leaving a nice flat surface to impact
with the next dart tip. Second, most people sharpen their dart tips
increasing the possibility of the RH scenario. With the common bristle
boards, sharp dart tips are rarely necessary. I plan to round over the
flight holders and intentionally blunt the dart tips.