I'm a big fan of Vandoren mouthpieces in general, and V16's in particular. I have rubber V16s for soprano, alto and tenor. I prefer the small chamber because on the rare occasions that I'm not playing alto in a legit style, I play more funk/louder stuff, and I like the small chamber a little more than the M I tried. The M was nice, and definitely more "dark and smooth"
Generally, Vandoren mouthpieces are excellent and don't need any extra facing work to play well, although many people choose to get them refaced because they are made from good rubber so they are good blanks. I have not played any modern Meyers, only vintage, but there are some who believe the facings on the modern Meyer pieces are inconsistent. A good facing doesn't change sound as much as response, but then again, therein lies some important tonal changes because if your piece is not responsive and you have to play your piece hard to get a decent sound, this can limit the colors you can get out of it. So, while I'm not knocking Meyers directly (since I haven't tried any) I would vote for the V16 7M, it sounds to me like what your looking for.