There's also the three Herbie Nichols Project recordings... two for Soul Note and one for Palmetto.
https://www.discogs.com/artist/3136938-The-Herbie-Nichols-Project
MAL-4 is also pretty essential IMO. Trio, swinging, but also documents another side of Mal's skills as an arranger. And "Love Span" might be the, uh, loveliest, performance he ever committed to tape.
Update: the Claude Williamson interview in question looks like it appears in the March 1997 issue of CADENCE. Not sure what volume and issue that would be, though...