ranger body drop ?

alright as alot of you know i totalled my ranger, so i am gonna start to stock floor body drop it to sit even lower...the ? is, how much of a sfbd do i need to sit 1/4 from layin door??i'm trad. body dropped 3 1/4 right now..when i'm on the ground i want the frame and new rockers to lay down at the same time..does anybody know or can some1 tell me how to get these measurments??