Steve, those shims were not any help. . .
to me.  I still ran out of threads on the clamps.  Went to Lowes and bought a 4" diameter rubber hose coupling complete with clamps, about $5.  With a slit to get it over the pedestal it looks good and protects the finish.  For wiring drilled hole in front of pedestal and dropped in a piece of string with a screw tied on the end.  Put a magnet up through a 3/4-inch hole from bottom and pulled the string out.  Used a correctly sized rubber grommet in the hole with the wire, also from Lowes.