That's a terrible way to approach young players imo. Produce as much as a 10 year veteran and don't mess up or don't play. The only way for young players to find rhythms and work out their kinks is to play solid minutes consecutively to figure things out and build confidence. Giving a guy 30 minutes one night then barely playing him the next does absolutely nothing for development and only makes a player put more pressure on themselves than they need.