Juan,
If we go back to your ideal set of specs -- the M3 fits it except for the aperture priority, or any meter at all. On the other hand, your statement of how you shoot suggests you may not need an internal meter at all. The M6 will give you that meter, but not exposure automation.
The M6 and R3 will give you the meter, and the R3, the automation.
So, if you want it all, Voigtlander it is.
OTOH, there is a wonderful feel, to both hand and eye, to an M.
I have not used a CL, though I looked through one when I was much, much younger. It has the advantage of small size and a 40mm frameline, but the RF patch simply did not look as distinct to me as an M3.
If money is no object, and meter is really an option, not a necessity, why not consider getting an M, since you already have an R. That way you can see which one YOUR hand, eye, and style gravitate to -- and if you choose the R, you will not lose much (any?) when you sell the M.
Buena suerte.