I am at 9 for the moment. It went up with the new defenders I got. But still letting them work their way in the team.
It's a personal feeling, but when I have new players preformance of the team is down for a day or 2 in my experience.
I am glad I got my defenders but would have liked it if I found em earlyer. They are bloody rare and like 90% of them is DC/DL combo.