12 players. TARGET stamina in recruiting (as in look for it, prioritize it, don't just take some good stamina if it's there). Make your SF position just a 3rd guard spot. So you'll want to have roughly 7 guards and 5 bigs.
As far as your breakthrough season..... at D2 it's nice to have 2 of your guards at 90+ SPD, High ATH across the boards. And one thing that's really important to me..... high scorers off the bench. If I have 4 scorers that are going to average double digits, I want two starting and two coming off the bench.
I'm not sure if you can track this nationally, but I would assume that I lead the country in bench points, every season that I have a contending team (E8 or better).