For anyone who’s remotely interested, and there can’t be many, this is how I arrive at my exposures when I’m outdoors with the Leica in the daytime:
a) 400 ASA (ISO if you must) b&w negative film
b) Leave the lens set to f8
c) As the light changes, I move the shutter between ONLY THREE different settings: 250 = bright AND sunny, 125 = bright or ‘don’t know’, 60 = near a building/in shadow
d) This leaves focussing. Set lens to 10 ft and be done with it. Use rangefinder if there’s time of course but using ’10 ft’ means you’re able to keep your eye on the ball and actually get the shot you wanted.