shackle mounts


hi i have a 1986 daihatsu rocky and i would like to extend the shackle mounts nothing serious about 3 inches, now i might sound stupid but you all know that each leaf spring comes with 2 leaf hangers 1 behind and the other one in front of each tire, and what i would like to know is if i extend the mounts does it have to be each hanger or just one of the two per leaf, please explain to me and you have pics its better. thanks i appreciate any help that i can get.