A few questions. Hope someone can help :)

[Gert Funck]

So value of a player also shows is he a fast learner?

Yes, if you watch auction:

two 18 yeared 5* players in ex level 1 can cost between 800k an 2,5M, the latter will then be the fast trainer, with up to 170 point with three bars training.

They are also the most popular, so there is always a risk off insane bidding wars (seen go over 100 rounds)