I have killed only one deer with a stone point. My points are longer . A short point like yours is stronger, but longer has more of an advantage in cutting. Mine are about 1 inch wide, 2 inches long, and as thick as the arrow. Perhaps even more important than that is sharpness and arrow tune. Obsidian makes the sharpest point, but you have to get good at the final sharpening process. You cant really tell from a picture how sharp it is, but the edge should be as straight as possible and with no leftover grinding marks, crumbled sections, or other dull areas. Getting the right spined arrows for the weight of the head will ensure that the arrow is traveling straight into the animal, not with its tail end wagging one way or the other. Only you can decide when you have an ethical combination of gear and technique.