All,
I downloaded the scanned files from BHS. You can view them on Google Drive at:
It's a total of 36mb or so - too big to email. I took a look and it goes all the way back to 1966. Looks like mostly lists of officers, articles of incorporation, rosters of members, etc from mid 60's to early 2000's, along with some correspondence between the chorus and BHS.
Starts with the Fergus Chorus - nothing that I saw from the Detroit Lakes Chorus.
David