Collision object inner/outer values vs cloth sim collision settings: related?

I’m trying to drape a cloth with some shape-key animated pins, but the simulation goes nuts whenever it gets anywhere near the collision object.

I thought it might a problem with scale, (the cloth is about 1/3rd of a blender unit wide - maybe Blender thinks I’m dragging it through the object’s outer bounds?) but I can’t seem to find any data about how the sim’s cloth collision settings relate to the object’s inner and outer collision values and what effect they have on each other, so fiddling with those hasn’t been particularly useful.

Any advice? TwT