lowering a longbed with leaf rear

[sir_talk_alot]

i saw one or two threads when searching, but couldnt find exactly what i needed. i wanted to ask what would be some ways, preferably cheap or cheaper way, of lowering a 1972 long bed c10 with a leaf spring rear end? i am wanting to do a 3/5 drop on it. so the front end all i have to do is buy drop springs, but the rear im needing some help. i saw on cpp that they have lowering rear leafs, how does that work? how much drop do i get from putting the leafs under the axle and using shackles? and is a c notch required or can i leave it without it? any help from all you smart guys would be greatly appreciated cuz im retarded when it comes to suspension.