re: Which Centers will be available this off-season?

Correct. Seeing that AD will finish every game at the 5, and Asik could give you a serviceable 18-20 mins there, SF is easily a bigger hole

A B-plus small forward helps this team far more than a B-plus center would. Now, a better than average SF is harder to land because there are far fewer of them, so there is an argument to be made that you go after a center instead for that reason. But a small forward is undoubtedly the bigger need