I ordered the Top Brass 19g Darts (variant 2) and i'm looking forward to throwing them :) Such a nice looking set for cheap

You made a statement that slow launch dart throwers should add weight to their darts. This actually will be adding a pendulum effect to the throw and slow down the already slow launch. You can't do that. Slow throwers shouldn't increase weight. They should lengthen the darts. They'll release at the same speed as before but this time the darts are better at flying in a straighter flight arc. Heavy weighted darts increase throwing variables. People need to graduate to heavier darts from a consistent throw from standard darts.