Moskva 2 rangefinder adjustment

Folks,

I have Moskva 2, a folding rangefinder camera in my posession.

Unfortunately, its rangefinder is way off the marks. After some

measuring it seems that both the distance ring around the lens and

most likely the rangefinder itself are misalinged. When I took the

ring off the front lens I found that its rim has long scratch marks

from the fixating screws, so the ring has probably slipped off from

its original position. The rangefinder also reports obviously wrong

distances (like ~8 meters for actual 2 meters).

The plan is to mount the ring into original position, and then somehow

calibrate the rangefinder. How can I determine what is the proper

position for the ring? Should it point to infinity when the lens is

fully screwed down? How should I adjust the rangefinder then?