remember, that if you have shortened the shafts as much as you safely can, and they are still a tad weak, you can tune your bow a bit to want the weaker shafts
1. by building the strike plate out a bit, taking the center of the shaft further from the center of the bow, will make the bow want a weaker shaft. You can do this by maybe adding a layer or two of double-sided carpet tape under the strike plate- it doesnt take much!
or a slightly thicker leather strike plate, or the soft side of velcro will also do it.
2.increasing your braceheight, will make a stiff arrow behave weaker
decreasing the BH will make a weak arrow behave stiffer
but lowering or raising too much will cause other problems, noise, efficiency etc.
its not something i would mess with too much, but will as a last resort.
just do a wee bit, and build the strike plate out a wee bit. a little bit goes a long way in all this.
good luck!
note on center shot bows- the raising of the Bh will have the opposite effect, as the power stroke is being changed.
whereas on non center shot bows, it seems to relate to the angle of the arrow on the bow- lower the brace height, the arrow points out further from the bow, making it behave stiffer!
the BH adjustment is such a contarversial topic, and results really seem to vary!!