I recalibrated my dad's CL's light meter by adjusting the trimming resistors as described. The instructions are great and the process works quite nicely. I needed about 30 minutes.
Two comments: (a) take it easy when turning the screws - a little goes a long way (specifically R5; 1/8th of a rotation was already too much). (b) the cover of the resistors wasn't made of aluminum in my dad's camera's case - it was a plastic strip. I glued it back on with styrofoam glue, that stuff is not very aggressive and hopefully still a bit elastic in 10 years' time when I'll need to recalibrate again.
Thank you very much, jeremy_tok, your description is great! Have a great day, Karl