I use the wide setting. I'm extremely pleased with the focal length setting I've been using for quite some time now with this lens/camera combination and have no desire to
"gain a bit of extra zoom". As it is, I don't use the maximum zoom on the lens as too much magnification would be counterproductive and would also increase the likelihood of excessive vibration in the image, especially on the rural dirt/gravel roads I often drive on.
As for sharpness, this lens produces remarkable results on the M1 using the full sensor with pixel binning. I see no reason to mess with results like
this. Pixel binning's effect on the M1 is barely perceptible as far as I can tell but all in all I've always found the full sensor provides a "slightly" better image. As an aside, another thing I can't help but marvel at with this 6-2mm ƒ/1.6 lens is the dramatically enhanced upper end dynamic range this lens provides to the Mobius, a camera not really known for good handling of bright highlights. Look at some of the images in the link, especially where bright reflections are seen in car windshields.