I have some remarks about the "size (px)" / "stroke width (px)" descriptions.
The "px" (or more precisely "virtual / CSS pixel") value for stroke in app would currently apply only for icon size value of 24 (px, matching viewport), what may seem quite misleading. "1px stroke" in "16px size" is obviously not rendered as full colour CSS pixel, and hypothetically might be rendered as one physical pixel on screen with 150% DPI ratio if they happen to be shifted by half CSS pixel. I'm pretty sure you know what I try to describe: SVG line with stroke-width="1" sitting on whole integer coordinates in non-resized SVG on display with 100% DPI scale will be rendered as "2px" aliased line around that pixel boundary.
It would be interesting to (try to) introduce option to have real (CSS) pixel stroke widths accompanied with mechanism that will align them on CSS pixel grid. (I'm not sure it is doable and worth the effort, because it presumably does not have universal solution for every single DPI, but maybe something could be learnt trying.)