i am training primarily single position with 3 guys. none of them are my best players, as my "starting 5" would be too old to consider proper training. next season, one of my trainees should be strong enough to be in my "starting 5" at that point i would probably sell him, or the guy he's replacing in top 5.
depending on the season i have been able to use this basic concept with training, sometimes sacrificing training for wins and minutes depending on the situation.