You should not have more than 8 players on your roster if you want 2 to play 48 minutes.
For me it works fine to set up as follows (if you want to train PG/SG):
blank / Trainee1 / Trainee1
blank / Trainee2 / Trainee2
Starter 3 / Sub1 / Sub1
Starter 4 / Sub2 / Sub2
Starter 5 / Sub3 / Sub3
Nobody knows, if there are now "new" coachs decisions if the players are "too" exhausted.
founded in S3 IV.5 (34234) - returned in S28 IV.7 (34515)