Something like that sounds good. I’ll leave the actions as pixels, which I think is the only term most people are going to understand.
I imagine there are cases where they are other ratios than Retina (2:1) and normal low DPI (1:1) if scaling is set to other settings. If there aren’t yet cases where that can happen, I’m sure there will be. Hopefully Keyboard Maestro works properly in all cases, though it becomes hard to test.
The wiki could mention “Points” as a possible synonym for these non-hardware pixel concepts, though I’ve mostly only seen that in relation to text.