If your planning investing more than 375T for 4 seasons of PTing a scout player including its purchase price, then its better to buy the 18 year old and PTing for over 8 seasons.
Going to the next star 75 skill point, if 1 day u make 10 PT + the player playing 2 match every day, so my suggest 1 day he gets, (10x2) + (2) = 24++ skill point, so in 3 or 4 days ur players going to the next level or u will get a special ability thats ur choice, if u manage 10 hours in 1 day....This refer to youngster 18yo. (btw sorry my english not really good, this just my theory).
i over spent this season already but i'm quite satisfied. Forgive me for asking too much as I want to be sure of complete understanding of the game. I have 1 8* and the rest are either 7* or soon to be 7*. The squad is 19 players with 16 of them under 24, meaning they can still train next year being 25 ( alot fo 19,20 yo as well). So what you say the cost would be keeping all these players 7 and 8 stars every season?
so how much booster needs to ur micu until 9* + SA, coz if push with token around 1k++ token
oh btw, you should mention using your first 50 skill points for SA or position will bring you little more advantage.