Parameters correspondance

[Jylomaki]

I'm trying to use clmtracker in a Augmented reality experience by browser, and I need the face 3D datas: the translation & rotation of the modèle.

I tried using posit algorithm, but it's not working very well (probably due to faciale feature not being very good parameters for it).
posit from here: https://github.com/jcmellado/js-aruco/blob/master/src/posit2.js

I read that there is the thing called Principal Components Analysis (PCA), and that it returns the parameter list.
(see here to fiddle a bit with those https://www.auduno.com/clmtrackr/examples/modelviewer_pca.html)
I could kind of get the yaw and the pitch but I didn't saw anything looking like roll or scale.

And also, what is the unit of those parameters? It is an arbitrary scale coming from the PCA?