My understanding is that if it were independent we wouldn’t have the requirements that are laid out in the docs, but there was a very good discussion on turbulence. I don’t know if it is useful to you:
That can be found here.
As for measuring y after meshing, we could look at evaluating the normals of the surface in paraview but from there I think it would become a lot of playing around to find the distance to the adjacent cells opposite face. But I reckon this is your best bet. It must be possible but might require some experimenting.
I tend you just rattle a simulation off for a minimal number of iterations and look at the results. In an ideal world, it would be great to have an adaptive layer meshing algorithm that could just keep adding layers until y+ is at desired value. Then we wouldn’t even be having this discussion 
But check out that link, if nothing else you will see the community members that have much more knowledge about the turbulence models than me and would be a great place to ask any further questions and keep all the turbulence model related questions in the same place to increase it as a resource.
Hope this helped in some way,
Darren