@Xeon, glad you find it useful.
I think you look too much into things that Glenn doesn't give a second thought about, having 50 years of drawing experience.08:40 : this is the first time I see Vilppu doing a direct drawing without any construction, and he makes it look so fast and easy! And I don't believe there's even a model in that vid! Someone need to setup an altar for this guy.
11:33: WTF was that!! The guy uses almost 1 - 2 fast lines to draw the contour from the trapezius to arm!!!! Mileage? It's more like inborn God-mode! Vilppustore needs to launch more Vilppu t-shirts so that more of us can buy them.
11:50: 1 - 2 line from trapezius to the end of lower forearm????
The essence of his lesson, are three things; planar form flow (2D), space (3D) and how to put them together, i.e. not having them collide too much and everything else in the video is irrelevant.
(planar form flow is easy since we've been introduced to it when we learned to read/write, but space takes drawing from life and any form of 2D reference, like a 3D model on the 2D monitor, unfortunately won't cut it)
So one should draw having these three things in mind and 'follow' the subject strictly, 'transform' it to one's personal preference while still maintaining subject correlation and 'repeat', further transforming existing transformation.
This is the only way to build your own 'style' and being relaxed is perhaps the most important thing, since any sort of awkwardness while working shuts your receptors down, effectively denying you essential 'follow' and 'transform' steps.
(note that Glenn's video predominantly dealing with the first step ('follow'), gives a few hints of 'transformation' too)
Hope this helps.