Very good C4DS, I didn't know for that plugin of yours.
But that not exactly what I would want to do.
This can be as a suggestion that you can implement and help people like me that must prepare UVs on multiple objects in multiple scenes(projects) that come together for Lightmap backing in some game engines like Unity or Unreal.
When you have done unwrapping UVs and created in that process a UV charts (multiple for one object) the best thing for me is that place for that UVs stay as I setup them. They should scale, not move. That means that objects UVs will scale proportional to their size for the set map size (i.e. 512). Later in another file (project) you can set the same UV proportion to that scene objects. You can put that input field it under Spacing and above Realine button.