a few torque specs needed.....also...spring clamps

leaf spring U-bolts, rear shackle nuts, and I think that's all....

also...
I bought some spring clamps....they are 1/2" square u-bolts, 2 1/2" wide, and use a 1/4" plate to clamp....
i have installed 1 per side, capturing the top 4 leafs.....first, how tight should i tighten them, and second, is 1 per side enough???