I saw them all, and I agree with you that the presentations were mostly exceptional. (With one notable exception, that being the 3 strip "How The West Was Won" at the Minneapolis Cooper Theatre).
Despite the engineers initial audio level settings, the local management had apparently decreed...
For roadshows, every theatre I ever either worked in or performance I attended when not working brought the house lights down to somewhere between 1/3 to 1/4 brightness and dimmed the main drape wash lights to 50% or so just before the start of the overture.
In addition exhibitors were not...