You can find Grassetti's tutorial + 3d ecorche on gumrod or a 10,- sculpt from Adam Skutt. I personally have Adam's sculpt in my ZBrush scene as reference to help me get the portions right and remember all the muscles. Just keep in mind he actually pushed all muscles a lot to serve as reminder and not as much as a…
The anatomy does look odd. Perhaps the armor is not well designed then. His shoulders look crazy high up...almost around his head. This definitely looks weird. The cape and the armor cover too much and you can't identify what is going on underneath. Maybe do screenshots of his nude, with the armor but without the cape, and…