I just received a Kiev 4M (Ukraine-built Contax II or Contax III variant made with repatriated equipment from the Zeiss factory). This is the version with a selenium (or silicon?) light meter on the top of the camera, just under the accessory shoe. It's a "center needle" type, where exposure is set on a dial around the rewind knob, with film speed scale in the old Soviet Gost system (Gost value is 90% of ASA, so Gost 100 film would be ASA 90), and you meter by turning the exposure dial until the meter needle is on the diamond mark, then read the exposure (shutter and aperture values) off the scale and input them on the lens and shutter speed dial.
It's a fairly simple meter to use, and more convenient than carrying a separate meter, though its limited sensitivity makes it less useful indoors (a very common issue with selenium meters).
What I'm interested in is whether it's reasonably easy to adjust this meter to read 10% lower, so I can set ISO/ASA linear scale film speed on the metering scale directly.
There's a tiny screw inside a protective collar on the back of the camera's top cover, under/behind the meter. Is this screw to adjust the meter, or the rangefinder? If the former, is a 10% change in reading practical to apply with this screw?