JMHO,   i think the mistake made here begins with the basic measurement 'the head' most CG figures i have studied the head scale is off by someones standard,   is there no standard upon which to base this basic premise, comparing one figure head to another and you will see a wild array of sizes... is there a 'standard head' upon which to begin? is it all subjective to 3d platform? the basis of eye width raises the same questions what is "standard" and is this standard universally acceptable? ...i find most publications on the subject contradict one another...looking around in 'real life' i find no easy answers, just compare the photos above of the real human models to one another and you will see what i mean... if you model a character to exactly match one of the models, its 'off' compared to the other two...

 this is what makes us human, in order to replicate humanity we have to incorperate variety, there is no universally acceptable model..we see the world from different perspectives...one persons trash is anothers treasure...

my thoughts are: we dont need to waste anymore time seeking 'perfect form' instead we should strive for variety, populate the CG universe with diversity as we find in the natural universe..it would get pretty boring looking at the 'same old thing'... just create 'your' example and do the best you can with it adjust it to your liking and make it as user friendly as possible...if it makes 'you' happy ,it just tickles me to death... even if it turns out to be 'perfect', someone will point out the fact that it is 'too perfect'....

:O)

Y'all have a great day.