The only thing I'd say its lacking is some step-by-step pictures... but I know how time-consuming those can be.
Oh, and the technique Rembrandt (and other Dutch masters) used that you made referrence to is called Chiaroscuro (or, directly translated "Light-Dark"). This technique was pioneered by da Vinci and other Italian masters, Rembrandt just took it to a new level, using directional light to single out subjectmatter, rather than using the dynamic effect over the whole canvas (as in The Calling of Saint Matthew). Anyway, good work, and thanks for giving us a place to start.
Joe