Vertex normal editor blender 2.8

Hey, there, sorry to necro. I stumbled across this when experimenting with moduler skeletal mesh setups.

I.e. I tried to split a horse in half and it resulted with a shading seam (which was expected).

Then I researched how I could overcome this issue and found many very unpleasant workarounds as well as these rather new normal tools.

Basically I want to average the normals along the seam, very similarly to what the migNormal tool in the original question does. Is something like this possible?

If not, where can I file a feature request :'D
Optimally, I would only want to trigger the existing average logic but for vertices that are not connected to each other.

After a LOT of trying, I finally managed to at least get the copy pasting to work, but it is kind of useless in this situation. I only managed by selecting a face, copying normal vectors, then selecting the vertices I want to paste them to. It doesn’t seem like I can paste the normal information of one vertex to another vertex directly (which would be an immense upgrade). This renders the copy pasting method completely irrelevant for my task as I cant create a face that defines my normal for each vertex, it just doesn’t scale.

Thanks for reading, hopefully someone has advice!

EDIT:
The following screenshot shows where the normals seperate on a disconnected edge of a sphere.
I’d like to somehow get them back together so they are as if the edge is not disconnected. I managed this (at least for spheres) by duplicating the seam vertices to another object and then using a Normal Edit modifier set to directional to kind of copy the normal information over, but this destroyed the complex mesh of my horse.

EDIT2:
With a DataTransfer modifier, I managed to at least copy the normals to the seperate pieces as long as I have a fully assembled mesh with the correct normal vectors. I reckon this is the best solution to this as of now, but a similar tool to the one described in the original post would be great.