That elastic effect is very powerful.
Yeah, it's always nice to draft a player with good complementary skills, so the elastic effect will make his training quicker.
But in any other case, I'm not sure training complementary skills first and then main skills is faster than doing main skills first, then the rest.. The main skill skill might train faster, but training all the other skills first will take some time, because elastic effect also works negatively, so the bad main skill will slow down the training of his other skills.
Personally, I think it doesn't make a difference.
"Air is beautiful, yet you cannot see it. It's soft, yet you cannot touch it. Air is a little like my brain." - Jean-Claude Van Damme