This is the rear. The insulator is at the top and the shim is shown at the top left.
I recall the procedure to remove the springs is here on the BB. Try doing a search and see what comes up.
You also might want to check out
this thread on corner weights. It explains why, along with a link to a Hotrod magazine article, proper corner weights are so important. Basically, just lowering the car by removing shims, insulators or spring cutting may not necessarily improve handling if the corner weights are afu.