[dsraven]

you're not likely gonna need the brackets or the extra leaf.
the way a normal leaf spring works is they may have a super thick lower leaf that doesn't touch the rest really unless there is a big load applied and then that becomes an overload leaf and helps hold the extra weight by not allowing the lighter leaves above it to bend so much. the other method uses a stack of leaves added above the original stack with either frame brackets to rub against when needed or else the ends of those overload springs are tied to the lower set of springs to aid in carrying the load. you could check the factory assembly manual and see the whole set up if you wanted.