Unicorn, brilliant for what you have included, however I don't see at any point where you are evaluating for a horses straightness in the forelimb, you say straightness is important but don't explain how to see that.
Being back at the knee or over at the knee are faults.Being back at the knee can be rather serious as it puts additional strain on the tendons and ligaments of the leg making them extremley prone to injury and breakdowns.
Perhaps an edit or addendum to your realy excellent tutorial. (sorry but horses that are back or over at the knee are a perticular pet hate of mine)
I can try to add them ... along with front and back stuff when I get the time.