Returning to the original post, I’m confused.
Why would Russell Metty, a Universal stalwart, be shooting a musical at the studio, with a 1.66 plate in his finder?
Since TMM was very early sound on disc, the correct ratio is 1.33:1.
No further discussion necessary.
Hopefully, the original six-track mix has been harvested from the original 32” wax cylinders. Precisely the same as MFL.