Subsonic implements a proprietary binary tree based mesher, coupled with a finite volume solver, that automatically tailors the mesh to give the right spacing at the wall. No explicit description of y+ is needed.
The wall functions are similar to those used with Standard K-epsilon models i.e. law of the wall. The wall functions include standard, Kim et al and Shih et al. But all these have proprietary tuning of the parameters that tailors them tothe binary tree meshing, and are therefore, optimized versions of what you see in the industry. The binary tree mesher of Subsonic takes care of getting the right grid resolution close to surfaces. This is inline with the wall functions implemented, and as such, users don’t need to worry about adjusting the y+ value or tuning the surface resolution to get good results.