My Summaron 35mm f3.5 came back surprisingly contrasty after a clean by Macom Taylor. When I first got it there was little visible haze but it flared like nobody's business if pointed anywhere in the general direction of a light source. Now I rarely bother using a lens hood as the front lens is quite deeply recessed. It is also very compact, not much larger than the Elmar 3.5cm.
I eventually sold my CV lenses because I just wasn't using them, razor sharp though they were. In fact I prefer the slightly softer more rounded tones of the original Leica glass which is, of course, part of the reason for choosing to use a 70 year old camera in the first place.