Muscle Shape is genetically determined. If you look carefully at the young Gironda you can see his innate shape which maturity and training developed. His unusual pec line that inserted lower into the humerus than with most trainees was already there as a young man—albeit in a less developed form. Same is true for split biceps with high peaks (Albert Beckles) or unusual splits in chest development.
One of the things Vince told me (privately) was that you should never try to build muscle where it isn't. He meant if you did not have the capacity for a certain shape (like not having upper chest developed ala Steeve Reeves) one should not attempt to do specific exercises in the hope of altering that genetically pre-determined factor.
This seems a contradiction to other things he said about 4 sides to a muscle, illusions, etc. But with enough discussion with him I realized it was not. The physiological logic behind his multiple exercises (though never stated) is that more muscle fibers can be fatigued which theoretically maximizes one's growth. Also, certain exercises are more likely to develop certain muscles to the fullest—in any particular trainee. For example, it makes sense to use lateral raises—for everyone—if wishing to develop maximally the medial head, thus creating an "illusion" of greater width when combined with a diet that kept the bodyfat low especially in the midsection.
The other thing to understand is that Vince was never married to his own ideas and was always experimenting. He was in competition with himself, and changed his mind at times—probably often. Nonetheless, genetic factors are central to any real understanding of bodybuilding—or Vince.
I trained a week with Freddy Ortiz (a Vince disciple). And though Freddy does not know it, his freakish upper body development (especially his arms) could have been developed doing most anything due to his genetically determined long biceps muscle bellies stretched across a comparatively short bone. Point is, no routine or biceps exercise—no matter how performed— will make someone else look like Freddy unless they have genetics just like him.
I have a friend who is a Mr. America winner. He has incredible legs, narrow hips, and proportionally developed glutes; a lower body Vince would have admired. Yet he squatted **all the time** as his main "leg" movement and deadlifted also. He looked that way because his genetics dictated the development.
The good news is that you can develop your own shape to its fullest likely using simple, equipment and incorporating isolation exercises (in addition to compounds). But there are usually several choices of either. So don't get hung up on any particular movement or the need to acquire certain machines. Proper understanding of physiology and kinesiology informed Vince's ideas. That knowledge is available to all of us with proper study. In that regard, books like "Gray's Anatomy" and some physiology/kinesiolgy books can greatly inform us. To his credit, Vince looked into these issues when nobody else did.
At the end of the day it is all really simple. Train smart, eat well, rest well, and genetics takes care of the rest. There are no magic routines or exercises. And that's actually good news.