it is also a difference of value, betwen your and mine situation.
You can easier afford to play trainees and still be succesful, while i had normally to train players who are wel develope before and don't raise their value that much(you can make it much more efficient then i do currently but not as good like you without sacrifying your succes).
The other difference is the value of extra won games, for me the difference betwen a lost and a won game before, in my none championship season around 70k i believe it is not more then 20k in your league.
Also constantly training gs and reducing the roster should safe me more salary then you, so training GS get more and more intresting the "stronger" your team gets. I would advice it for a rookie just for very very important games, while it could make sense to train it constantly as a div 1 team.