Tried posting this at http://gurneyjourney.blogspot.com/2010/09/caricature-and-likeness.html, all attempts failed! Seems I may be considered spam. BLogger, less fun every day. Check your spam boxes for hidden goodies!
"muscle memory" Exactly, practice what you want to learn, in the way you want to practice it.
I recommend with some trepidation Lasar's book, Practical Hints for Art Students, for though it has much information, and is ostensibly for amateurs, it may be too dense for most. He does not discuss it, so I fear the angle machine is lost to history. I always imagined it as a kind of segmented & hinged ruler. Useful?
from Lasar~ "Consider your drawing as a star before putting it into movement, then bend the points of the star to suit the subject."
Note how Lasars figure abstraction and the controlling of salient points relates to the ideas presented here~ Doug Higgins
The first exercise in The Art of Drawing by Willy Pogany is a sight-size lesson meant to develop your judgement of Distance, Direction, and Proportion. Pogany uses dots in the way Ruskin, if my memory hasn't failed, advocates using line drawings of fauna. Free-hand copy and self correct by overlaying.
""Well, there's a job I'd like to have. :)"" re:Lasars
I called, but they were no longer accepting applicants. :(