Let me suggest even something else that does not require an extra guy: out of the cup? think a PG or your SF could use a round of inside shot? Go ahead and play them in your scrimmage at no cost. Yes, you'd have to blow some games in your main competition (or perhaps get temporary bacups for your PG and SF), but you could make up for it after you'd be out of B3.
Make it based on size and do it in a hurry before we see our first 30k arenas.