A Guide for fast trainers

[Tactician]

I have seen a mixture of recommendations for power training. A senior has recommended the non-free academy players, and now I see that 'nordgens' are recommended.

But, I am not interested into that level of power training as I can't afford to buy so many tokens, especially for green packs.

So far, I agree that 'nordgens' are the best investment for the low-average token buyers.

I have not bought any scout players so far. What is the flop chance for a scout player?
What if you invested green packs on a 22 year old scout player, does he become a superstar? How fast is his gain in skill points?