The problem of all this, and thats why a SA can not be perceptible, is that the 1* is applied in the internal base of the player.
This "unlocks the SA" when this is completed, but if the inter4nal margin is too low, then is when the SA is not perceptible.
And for my calculations the external skills affect the internal ones in a proportion of 1/8 - 1/10 aprox.... even less in many cases due a "max. in the skill capacity by default" .... because we've seen players at 340% that literally "do nothing".
As always, a star player, can not be created, a star player should be found and developed. And this needs the sense of the understanding of "how to find a well player to be capable to develop X or Y job".