Here is my player I signed about 9 seasons ago for 6 tokens. Since then he has always finished each season above 140%. He reached 150% at the end of last season so it was easy to train him back to 140% this season after he got the - 20% quality. It cost me about 100 rest packs that's just 3 days of farming. I have about 8 other players like this so it's very possible and easy.
The best of the best