I finally had some time this afternoon to install my Ken's bolt-on grab hooks. I am really impressed with the build quality and the ease of installation. I had originally intended to install three hooks across the top and two shackle mounts on top next to the outer hooks but then I saw a post from someone who had mounted the shackles under the grab hooks in place of the backing plates. It makes a cleaner install and allows the shackle support to dangle straight down to the load even when the bucket is raised all the way up.
I may add a third shackle mount under the center hook.