Organist Alexander Schreiner (above) talks to organists at the sanctuary of the State Hospital in Provo. The organ behind him had been recently installed. Schreiner played several pieces on the organ, including (as I recall) Louis Vierne's Naïades. (FWIW, Alexander Schreiner is Barbara's great uncle.)
One of the stops at the convention was the Provo Tabernacle. The organ there has been rebuilt completely since that time. The pre-rebuild organ was used for my graduate recital.