And/or the Morph Merger plugin:
https://hub.virtamate.com/resources/morph-merger.142/
I would call both plugins "must have" for VaM morph manipulations.
With the Mass Manager you can mix two looks, or one look with the VaM default settings.
It can be used for different body regions, but unfortunately it has issues with dividing full body morphs.
The Morph Merger can merge a large set of different morphs. It can save a merged morph for full body, or for head/body, so you can mix different heads and bodys. This is somewhat static, because of merging, but reliable.
Instead of manipulating some morph values at runtime, you could just save some sets of morphs as single new morphs and blend between them.
If you want to have it more flexible (but also more complicated) you may want to take a look at the Morph Editor plugin, too.
https://hub.virtamate.com/resources/morph-editor.8073/