No potshots from here Jon. That agrees with how I understand them. There is "Rider" which seems to be a lover/sex-partner, and "conjur man"--a which doctor. Usually he is used to get rid of spells (or just the blues) in the songs.
In "Nobody's Dirty Business" Mississippi John Hurt says he is going down to Pensacola to get his love what sounds like a "money mola" I can't figure out what that is.
There is a discussion of the meaning of some of these terms in LeRoi Jones' "Blues People".