With only 1" of suspension travel left in rear-end, you'll want to increase spring-rate to not bottom out. To have 1" travel for same bump that would bottom stock suspension, need to increase rear spring-rate by 4x to 37kg/mm from factory 9.3kg/mm. Along with reducing compression-damping and increasing rebound-damping significantly in shock. Otherwise, bottoming suspension and hitting bump-stops while in middle of corner has disastrous effects...
Maybe you'll want to look at
Eliminator 250, uses same engine as Ninja 250 pre-gen...
I once heard a saying: "
rather than trying to cover entire world in leather, just wear leather shoes..."