viboons
Established
The Version 1 8 element Summicron is one of my favorite lenses. It is very well behaved and meets the description of your needs very well. I would not call it low contrast, but very natural contrast, without the zingy look of the 6 element, or some other later Leica lenses. Still, its performance is more like the version 4 than you'd expect.
My own experience is that there is more variation in these 8 element lenses than in other Leica lenses, so getting to compare several is an ideal situation. All I've used are similar stopped down, but some were noticeably better at full aperture. They are also prone to some easily cleaned haze on an inner lens surface.
After saying all of that, I still think the 35 Summilux (pre-aspheric) would be at least as good a choice. Full aperture is not all that great, but usable and often interesting. At f2 it is a touch better than the pre-aspheric Summicrons, especially in regards to vignetting. From f2 on it is up to individual preference, but the Summilux and 8 element are very comparable. Size is great, price is often less than the 8 element Summicron, and resale value has held well. I've not tried as many of these as the Summicrons, but my impression is that they are very consistent in performance.
I only can have a chance to try before buy only one 35 lux pre asph # 26xxxxx. Would the later one #32xxxxx be a better lens because of later make? But this one I have to buy first try later. I also like the vintage leica look of the image I took with 50 lux pre asph, inherited from my father in law. May the 35 lux pre asph do the similar look?