Thanks for replies.
I bought a 5*, 19 years old AML/ML for 4,2M. His based price was 4,89M. He was missing 13 Skill points to reach Scout Level.
I had 27 Green packs and I started to train. The average gain was about 38/80/115+-.
I reach scout level some hours later, spending many green Packs. Now the Packs are gonne, and I have zero of then.
My player has 36 quality (started with 34).His value now is abouit 5,5M. He played a match and did 4 goals, what leave me really happy.
I will keep him without training sections untill the weekend, when I will spend all the green packs gotten trought the week.

I have only 1 regret. Maybe was better If I had trainning a specialization on him before He reach scout level, becouse after get it, the average gain decreased a little.