The president ought to channel Lincoln at Gettysburg as much as he can get away with, probably drop "score," make "a few appropriate remarks," keep them short, the better for impact, be general and in the clouds (where the "better angels" are anyway), speak softly, let the listener strain to hear the words, the better to make them stick, it is a funeral after all, as that was, so use the KJV as much as he can get away with, keep his head down, that encourages the listener to concentrate on the words too, be humble and speak softly.