I've known several Cinerama theaters, but I believe I've only ever seen a couple of the actual 3-strip films in them. Those would be the first couple of the travelogue features of the 1950s, when my grandmother would take my sister and me on a bus from Columbus to Cincinnati to see them in their roadshow engagements. Columbus had a few wonderful movie palaces but it didn't have a Cinerama theater. Cincinnati would have been the closest city with one.
We didn't see "How the West Was Won" till it went into general release on flat screens, but I well remember how it looked with the visible lines between the three panels.
The only other "Cinerama" films I saw in their original theaters were those projected from 70mm, even though they used the Cinerama name: "2001", "Mad World", and the like. Even the fabled rereleases of "This is Cinerama", such as at the Dome in the 1970s, were 70mm, not 3-strip. But I have a real fondness for all of those movies, even the kitchiest of them, and I have all of the Smilebox releases. Looking forward to "Brothers Grimm".