Your going to run into shackle angle issues.  3 leafs and an overload wont support the truck with the bed on it.  Trust me you know Ive been down that road....  Once the truck is back together those shackles are going to lay down a lot.  If you'll move the hanger ahead about 1/2-3/4"the tire will line up in the wheelwell once weight is on it and the shackle angle will be about right on.