I dropped my speedster 4 inches by using a T rear spring and only leaving in I think about 6 maybe 7 leafs. For a rootlieb kit, this would be plenty sense there is not weight in the back of them. My speedster is a boat tail, that had the 15 gallon gas tank in the very back. It does bottom out when I hit a big enough bump. I haven't gotten to adding shocks yet, but I'm probably going to have to drop the rear end and add a leaf or two in the assembly.
My cars getting the upholstery done right now, so after this Friday I should be able to post pictures of it completely done

. Be looking for that thread this weekend or within the next week or so. I also only left like 5 leafs in the front spring. This dropped the front a little, but not a whole lot. I really only took out some leafs in the front since there wasnt going to be a whole lot of weight up there. No fenders, hood, or any go slow stuff up front.