Corrective Smooth Better Rest Sources

I deal with Corrective Smooth a lot, and I always have to plan around the issue of the rest source, and changing the vertex count via modifiers.

If I could point to a mesh of same topology / vertex count as the "Rest Source", it would open many avenues to use it at the expense of having just a duplicate object.

As an example of why I'd want that, I have a mesh that I want to use weld on to separate strands of hair. In my workflow I need to have those weld modifiers be the start of the modifier chain, even before armature. Therefore there's no way I can have both the weld and corr Smooth modifers.