I'm collecting my M240 tomorrow but today I went to a trade show and spent a good hour or two at the Leica stall. The thing is I'm not sure whether I'm a natural 50 or 35mm person. However for street I might be better with the 35 - the DoF of the Summicron f2 looks rather useful whereas the 50 DoF scale is more compressed, which is to be expected. For zone, DoF is king, isn't it.
Maybe a summicron 35 f/2 now and a Zeiss sonnar 50 when my credit card allows.
I thought the 50mm focal length would be perfect for my main lens when began with my first Leica almost threes ago as that was the focal length I'd been using on my previous camera. I photographed for at least 6 months with the 50. Then I thought I'd like to try the 35 focal length. It took a while to adjust but find it is now my go to focal length. What I think helped me is I only had one lens at the time. I didn't have an option to switch lenses regularly. It forced me to learn that lens. I would suggest the same until you get comfortable making photographs with a rangefinder. By having to move my feet vice swapping lens has helped me immensely. Before I raise the camera to my eye I already have a pretty good idea on how I have the photographed framed the way I want it. All I have to do is click the shutter.
This was one snap a couple days ago: