How to get distance between 2 bones with offset

I want a bone to move based on the distance between 2 other bones on an animated SkelMesh, with an offset for bone position. What Blueprint node network would work for this?

The plan is for distance-based rigging to go off when the character rotates the wrist upward, then an armor plate bone will slide. I am an expert Maya user, but I am a beginner with Unreal Blueprint nodes. In Maya, I would just create a Distance Measurement between 2 locators, then connect the distance to a setRange node, to drive translation of the armor bone based on distance.

I found “Get Distance Between 2 Sockets”, but I don’t see where I can add an offset here. So I probably have to make some more nodes that get the translation offset in X, Y, Z, then create a vector between those offsets, and that will give me the current distance. If I could get the distance, I can use Normalize to Range and Transform Bone to move the armor plate bone. When the distance is short, the armor will move out of the way. But how to arrange the nodes to get the distance?

I want to have an offset so I can avoid adding sockets just for this purpose. Maybe there is a way to temporarily add the socket, and move it, just to get the transform offset?

Best bet get location of sockets and do vector distance between those world space or local space vectors. As socket location in world space will include any other positional offset You can also grab direction this way. Giving you unit vector direction and distance as float.
Hope this helps