All the best with the M4. It is "made" for the 35mm lenses, as the framelines for 35mm nearly fill the viewfinder. I like that, some prefer to be able to see via the viewfinder what is coming into the field covered by the framelines - as you can do on the M4 with a 50mm lens fitted.

the Nokton 35mm f1.4 (which I do not have) gets different reviews from different people, some of them quite experienced photographers: see the threads at Rangefinder forum for example.

I love collapsible lenses while they are collapsed Nice and compact, looks cool. But don't forget to pull the bloody thing out and rotate to lock before hitting the shutter button. I reckon almost everyone has stuffed this up at least once. I'd suggest a rigid Summicron (have one) or one of the Voigtlanders. And the Elmar f4 is a just so-so performer (have two - one refurbished by Sherry Krauter) - try for some other 90 for the long term.