It seems like the current vorpx in-game motion controller position matches the real world position.
Knowing this I set the floor to the correct height, by placing one touch controller on the floor, looking down and adjusting the 3D strength until the controller height matched the floor height.
So far this gave me good results with scale and removed the weird standing inside/above the floor effect.
The scale (correct me if I’m wrong) should be pretty accurate (+/- 10%) in a first person game with somewhat realistic scale (for a person with average height).