Hi Blastframe,
I hope I was able to catch your idea. It is always easier to talk with an example file.
Please have a look at this file:
https://www.amazon.com/clouddrive/share/LlTZme0k73KZKkEAtEMV83Gm7LjiGYNVkt6Qcj8AKKa
I copied and pasted the Base and the Pose layer, but each copy was then set to “Post Deformers”. While the Pose Deformer is at the same time restricted. So, it works as the deformer is set up or the Pose Morph.
Since I never had this question, nor its need for it, please test this file, and if there is anything not working for you, perhaps it helps to create for a single moment a shape to your liking, which could be then harvested (Current State to Object) and used as is as a new Pose Morph (absolute). Place this object on a extra layer, to keep things save and organized.
All the best