Let's aim for top players.
130 TSP +. Need at least MVP potential. Let's train efficient with 3 guys. We know we won't make every week full training, so we need 2 MVP talents or higher and one Superstar. The superstar will reach 120 TSP.
My scheme for 130 TSP is as follow.
start 18 50 TSP
start 19 63 TSP
start 20 74 TSP
start 21 85 TSP
start 22 95 TSP
start 23 104 TSP
5 seasons average speed 11 TSP a season. In my Utopia team at the moment with a lvl 4 trainer I have done that. So there is no special need for higher lvl trainer. Smart training is way more important!
start 24 110 TSP
start 25 115 TSP
start 26 119 TSP
start 27 123 TSP
start 28 127 TSP
start 29 130 TSP.
The scheme is an indication, but when a player is too far of, than 130 TSP will be impossible to reach.
So 10 seasons of training cost 8 million see previous post.
acquiring talent. 1 draftee, buying 18 year old 50 TSP MVP, buying 18 year old 50 TSP Superstar. Draftee will cost 60 points? 1 draft point cost 5000. So 300.000 for own draftee. Buying the two others will quickly cost you 2.5m at the current market.
So total cost 10.8m for 3 players. So 2 times 4m for a MVP 130 TSP's at age 29 and 2.8 m for the superstar with 120 TSP at 29.
But there are two hidden factors. One at the cost side. Because of training the team will underperform. Depending on the level you play and the country, I assume it can cost between 400k a season and 2m a season on fewer income. Because of the training you will lose games, not promoted, etc..
Advantage when the trainees are fully trained specially on your own drafted one, one will get a lot of extra merchandise, specially when such player plays in the National Team. So in the golden seasons 29 till 33, one will get extra income through merchandising, which can lead to an 1m income per week in a top league. 1m income can give you a stable economy even with a salary post per week of 900k. Assuming you get far in the Play-offs and cup.
Not much of a formular, but I believe a nice and simple guide, to see if a player is worth the investment.
Only in the dark, we succeed!