Originally Posted by EsJayEs

On the shims, you got it. They're really that simple!

Here's why I recommend buying/borrowing/renting a torque wrench for this. The shackle will bend inwards on the leaf spring bushing. By the time you realize that it was too much tightening, it's too late. You have to pull it back out, straighten, and try again. It's an awkward bolt because it never seems to feel tight, so you instinctively keep tightening. Proper torquing ensures that the shackles will stay straight, are tight enough for safety, and will never cause damage to the bushings (that would ultimately result in a suspension squeak).

I know AutoZone and Advance rent tools for free. You should see if they have a torque wrench. Ounce of prevention, pound of cure. You get the idea...