Well, because my most promising trainee messed up his minutes this week and I figured that he shouldn't just play with backup players or this might affect his performance, and therefor his training, or am i thinking wrongly on that too?
Does his performance in a scrimmage really matter? I don't think so. And it's not or at least just very little influenced by his backup players.
The only thing that matters for his training is the amount of minutes he plays in a week on the training position(s), you don't need to pay attention to his in-game performance when it comes to training.
Actually it could be worse. 75 minutes is not that bad (it shouldn't be more though...). But in general, do you know how to manage your players' game shape?
No I don't, I just play the 4 best (excluding training spot of PG) for both matches in the competition as starter, with other 5 as backup. PG spot I played trainee A play 1 match starter and 1 backup and reserve, player B 1 match starter 1 match backup and reserve, scrimage with player C as starter and A or B as backup and reserve if they needed the minutes. I did it like this because my 3rd PG was 31 yo and not trainable.. I will however since I now aquired a new trainee PG to 1 match for all as starter backup and reserve.
If any of your players has played 60 minutes or more before the scrimmage, leave them at home (unless you need some minutes for training maybe). Any further minute will not help their game shape.
You may consider something I've done. I've bought myself a really bad player (600$ salary at the moment) so he can play in scrimmages if all other players have already collected enough minutes for that week.
Alternatively you can buy players from the TL for 1000$ to play in the scrimmage and fire them afterwards. This way, you avoid paying those bad players their salary but you can optimize your other players' game shapes.
Does this make sense?
We have both said a lot of things that you are going to regret.