A few things: CdS meters were not perfectly linear even when the cameras they came with were new. There are a few ways you can handle this. Typically, as has been mentioned, the non-linearity shows up when the light is lower. If you use a roll of Portra 400 and set the meter to 200, your photos in good light might be slightly overexposed and those in poor light should be about right. Color print film has some lattitude and that lattitude should take you the rest of the way. You can get a hand held light meter. You can adjust the ASA dial at the beginning of a day's shooting based on a known accurate meter. This would be for using a 1.5 volt battery in a camera made for a 1.35 volt battery. Most people no longer shoot slide film. It is expensive and has very little exposure lattitude. If you want to shoot slide film, look for a camera which does not have a CdS meter. These would include the Minolta X-700, Canon EF, Nikon N90S, Canon New F-1 etc. Presumably you are looking to get some enjoyment from your picture taking. Don't worry that your camera's meter is off by 1/10 of a stop. The perfect doesn't have to be the enemy of the good.
Minolta's first 35mm SLR was the SR-2 of 1958. It introduced the SR mount. That same badic mount is found on cameras even after Minolta stopped making them. Manufacturers in China and possibly also Japan sold them in the U.S. under the Vivitar and other names. The SR-2 did not have a built-in meter. Clip-on meters were later made for SR series cameras. The first Minolta interchangeable lens SLR with a built-in meter was the SR-7. This camera had a meter cell on the outside of the body. It did not read light through the lens. As such, the Auto Rokkors were not meter coupled. What was auto about them? They had auto diaphragm operation.
The SRT 101 of 1966 had built-in through the lens metering. This required a tab to transmit the aperture setting to the camera. I have seen a few odd cases where someone attached a meter tab to an older SR lens. The SR mount changed again in 1977 with the addition of the MD tab. Some of the early MC lenses, like the 58/1.4, were carry-overs from the previous Auto Rokkor designs. Minolta did not make important changes to the lens coatings until the introduction of the MC Rokkor-X lenses in 1973. You can use Auto Rokkors on later cameras with stop down metering. To slightly complicate things further, in the early SR era, Minolta took some lenses from the earlier rangefinder models and put SR mounts on them. These lenses do not have auto diapgragms. For regular picture taking, any of the MC Rokkor-X, MD Rokkor-X or plain MD lenses will get you the best results.
