I also remember him best as Clayton, Benson's main comedic foil. I recall one episode where Clayton became so upset over Benson winning some award that he (Clayton) had a sort of mini-breakdown and started behaving as if he was Benson, adopting Robert Guillaume's "Benson DuBois" mannerisms and even showing up to work in brownface (it was ~1984) and referring to himself as Benson. RA actually nailed most of Guillaume's style so well that even Benson had to keep looking aside to others and saying (essentially) "I really do that??" To get Clayton to snap out of it, the psychiatrist had to have Benson dress up as and imitate Clayton so they could have an 'encounter'. It was a thin story but an acting challenge for both actors (but mostly RA).
Now "Benson" (Guillaume), "Governor Gatling" (James Noble) and "Clayton" (Auberjonois) are all up in heaven, bickering over governing that state they never identified.