Thank you Bob. Those look really nice! Since I sold my RX1 last summer I haven't had a 35mm lens and really miss it sometimes. I have been thinking about the Ultron 35 and there is a used one for sale which is very tempting. I think I'll buy it and give it a try.
I'm actually considering selling the Loxia and keeping the C/Y 50/1.7 for urban stuff and landscapes in dull light and the Nokton for everything else. The Rokkor is a lovely lens so I'll keep it for now. It'll see more use in spring and summer when I enjoy walking around in the forest and do "bokeh shots".