When you say 'blank lineup', do you mean you just select the guys who can play at the top. Then set tactics and leave the rest?
Yes.
I have no experience with this at all. Although I am intrigued to give it a go.
Yesterday, game shape 7/10 players again on 9 GS. When I was managing the minutes, I never had more than half of the players on GS 9. Try it if you don't train or have only 1 trainee.