on the shims either get the hardened ones (black in color), or shim under the cup. they will be different size depending on which way you go. Damper cutting into regular shims is usual.

Within .015 of installed height is acceptable.

Installing the seal is usually a 1/2 inch deep well, and a plastic water bottle cap to save on the palm of the hand, with a little wiggle, and a press with the hand. Go slow it will go fine.