Thanks for your answer.
So, if I understood you correctly, to ensure that my trainee gets 48+ minutes in this game I must put him at Starter, Backup and Reserve position? I usually leave reserves empty.
48 min doesn't work, because starter + backup lead to 5 missing minutes.
So make your lineup like that:
Trainee A / Trainee B/Trainee B for the forfeit game which leads to 36 min for player A and 12 for player B
And play your Cup match like that(i hope you get the blowout against the bot):
Trainee B/ trainee B/ Trainee A
Which mostly leads to 36 min for Trainee B and 12 for Trainee A, but sometimes A get substitutes in the last three min of the third quarter and gets some extra minutes so this isn't working everytime.