Copies After Velasquez- A Study In Technique I

I began a series of oil copies of a hand painted by Velasquez in order to clarify to myself some of the different technical approaches I am aware of.  I chose the hand because I wanted something I thought I could paint five times without going crazy.  I also wanted to start all five with the same cartoon transfer so they would start out with the same exact drawing.  Next time I do something like this, I will work from a very simple object from life.  It was, perhaps, not a fair set-up because it may have limited color interpretations and textural interpretations.  The other difficulty is that of labeling the techniques.  I settled upon labeling them with a broadly understood term or the great painter that I associate with the technique.  Another limitation I ran into is that, really, this is a "first" painting.  There wasn't much visual information to go beyond that.
Labels and Working Distinctions 
Van Dyck and oftentimes my familiar method:  Transparent shadows first in Raw Umber and when dry, underpaint thick lights with Flake White.
Grissaille:  Opaque underpainting, mixing Raw Umber (some use a warm black or green earth) with Flake White on the palette and painting a covering layer lighter in value than it will need to be later on.
Academic Method/Ingres:  Greater care given to line and an opaque dead color stage for an underpainting.
Rubens:  Transparent shadows, cools and warms kept in separate layers and on separate brushes.
Assael: Start with opaque and higher chroma midtones and build lights and darks into them.  Sculpting very thick highlights.
Grounds
All grounds are Claessens 13SP (single-primed)
Van Dyck:   White ground
Grisaille:  White ground
Academic/Ingres:  White ground
Rubens:  Gray toned
Assael:  Venetian Red toned

See Image 2

Before Day 1.....In order to keep things similar from the beginning, I transferred charcoal drawings onto each canvas.  However, below I pretend that I am working from life and describe what I did each day under typical working conditions.  Remember this is a very simple, small subject and it would take more days at the later stages for more complex paintings.

The Subject: Image 1

The Grounds: Image 2 Rubens

The Grounds: Image 2 Assael


The Grounds:  Image 2: All other grounds remained white