brent, i think the washer is actually the head of the metal insert. i mounted my 150 with the fmb to the under side of the top of the ent center. it fits about an inch or two above the plasma, and is slightly tilted down. the tilt improved the performance, and made the bride very happy that she finally could put her framed print back on the top of the cabinet. i think i got to sleep in the big bed that night.
dan