Ross Laird has three volumes of discography of Brunswick records. They are expensive, but, fortunately, they have the amazon feature "search inside."
This is the volume of interest here.
Brunswick Records: A Discography of Recordings, 1916-1931
Volume 3: Chicago and Regional Sessions (Discographies)
Here is the relevant listing.
I point out the note after the listing of "Clarinetitis" and "That's A Plenty."
This information is also found in vol 2 (New York)
Mike told us of Benny going to Chicago with Sam Lanin. Benny has an account of this in "Kingdom of Swing." In May 1928, Ben Pollack gave notice to the management of the Little Club assuming that he had a pit job in the musical "Say When." [Note 1] However, the local union nixed the job by claiming the Pollack group was a "traveling band." So all the guys were stuck with no jobs for the summer. Benny writes,
"Harry and I got a break snagging a date with Sam Lanin, who took us on for a week to play a convention in Chicago at the Congress Hotel.
So the combination of matrix numbers and Goodman chronology confirm what Rust had been writing all along: the Clarinetitis session took place in Chicago on June 13, 1928.
I am surprised that Connors, the distinguished Goodman bio-discographer had a convoluted argument in support of his belief in Goodmans recollection that the "Clarinetitis" session had taken place in 1927. There may be an explanation. When you know a person well and like/trust him/her, sentiment sometimes overrides reason.
Note 2. Chicago Tribune, Jun 15, 1928
The first annual convention of the Delta Phi Theta, sorority will open this evening with a dance in the Florentine room of the Congress Hotel. I am guessing that this is the convention that Benny referred to in his biography. I dont have access to the Chicago Tribune files. Does anyone?