This looks awesome! I really like how much effort you’re putting into getting the node interface right. Maybe “K” and “Radius2” could still change? I’m guessing “Radius and Radius2” are the inner and outer radii.
Also, I briefly looked around the internet and I haven’t found what SDF actually stands for. Shadertoy distance functions? I’ve noticed some acronyms being added to Blender recently which can make it harder for new people to learn. Could it make sense to expand the name and not use the acronym? I understand there are probably lots of reasons why it wouldn’t.