Slight correction to Petewick. Tommy Duff was the manager for most of the Rex's existence. Mattie Gilchrist was the cashier though I think she may have taken over as manager for a time towards the end after Mr Duff retired and before the cinema closed. Ronnie Hamilton was the last 'Chief' (chief operator), with George Harvey as the 2nd.
The Rex was indeed the bigger of the town's two cinemas at 1200 seats against the Picture House's 470 (reduced now to 265). It was opened in 1939 (I have somewhere a Courier containing a report of the opening, whch was performed by Provost Greenlees; I must try and dig it out and see if I can work out how to scan it for posting here) and was owned and operated by the George Green company that had a chain of cinemas stretching from Campbeltown to Dundee abnd including the Scala in Dunoon. The famous Green's Playhouse in Glasgow was the largest cinema in Europe and later became the Apollo.
There was originally a tearoom in the balcony foyer but that had gone by the mid to late 1950s when I first got to know the place. Power came from a diesel generator housed in a wee building at the corner of Shore Street and St John Street, diagonally opposite the Masonic Lodge; later mains power was used but the wee house was used for the rectifiers that converted it from AC to Direct Current (for the carbon arcs that lit the projectors). Though I might be expected to make this claim since I have a long connection with the smaller cinema, it is generally accepted that the Rex always had older, inferior equipment to the Picture House in terms of both sound and projection and the bare plaster walls of the auditorium gave it a very 'echoey' accoustic. When Cinemascope came in around 1955, the Picture House put in the proper curved screen and full Cinemascope installation, while the Rex simply put in a flat screen and stuck some standard anamorphic lenses on to the projectors. It did the job, but the picture quality wasn't ideal. In front of the screen was a very colourful curtain with a desert island and palm trees motif, but it was seldom used as it was hand operated and was a b****r to open and close. There was also a set of gold 'house tabs' at the front of the stage which could be used for concerts and the like (also hand operated and, as I know from bitter personal experience, also a b****r to open and close). The stage itself wasn't very deep though it was certainly wide and didn't have much wing space. When the drama festival went into the Rex every year (until dwindling audiences and the refurbishment of the Victoria Hall made it the venue of choice) they actually built a full procenium stage and lighting rig on top of the existing stage. (How the drama festival has dwindled can be seen from the fact that people used to queue round the block to book for the 1200 seats of the Rex whereas now they're lucky to get 200 into the Grammar School hall for it.)
So far as films go, the Rex used to get pictures before the Picture House because it was part of a chain, at least until Cinemascope, when the Picture House had first claim on any 20th Century-Fox product because they were the originators of Cinemascope and the Picture House had installed their actual system. The programmes changed three times a week (Monday, Wednesday and Friday) unless it was a big 'blockbuster' on first run, when it often ran the six days. All the Rex's programmes included Pearl and Dean and the latest Pathe newsreel (the Picture Hoiuse had Movietone, again the 20th Century-Fox connection).
The seating was pretty standard apart from the famous 'Golden Divans' on the first three or four rows of the balcony. They cost extra, but were very comfortable right enough. Known locally as the Golden Dive-ins. Must also mention the carpet which had a pattern that included the legend "It's Green's - It's Good!".