3 or 4 years ago, as I was then the archivist for Hollinwell (Notts Golf Club) I was approached by someone called Eugene Chan doing research into the length of golf courses in the Golden Age. This was because Hollinwell has always been a long course (6,770 in 1935 then 6,931 in 1957, reaching 7,020 in 1981 for example). Later on he passed on some of his research to us as follows:
Carnoustie 7,200yds in 1937
Oakland Hls 7,037 in 1937
Holston Hls 6,993 in early 1930s
Oakmont 6,965 in 1927
Portmarnock 6,958 in 1938
Riviera 6,910 in 1929
I think I still have his email address somewhere so could ask if he got any further with this if that helps?
Cheers,
James