As the next step, I decided to give a test to the resulted Sculpting base.
Planar head model was pretty good example, but testing better be quite stressful so this time I decided to draft an Écorché.
Mutires level 6 gives 10mln vertices while remain fast enough, but I decided to use Multires level 4 which gives ~600 k vertices.
I made a sketch of a realistic male shape following different anatomic guidelines, then I assigned shapekeys, and here is how it looks like.
In my opinion the topology works pretty nice, but I am not sure if I am confident enough in this area.
So here is a separate file with the resulting sculpt and shapekeys (Sculpt_base_Ecorche_v01.blend)