I'm actually planning on 8-team divisions, not 4-team divisions, so there's no worry about splitting each division into 2. I'm just trying to decide between "North-South" or "East-West" for each conference. Currently, I have the AFC set up to be East-West, and the NFC set up North-South, so the standings look like this:
The 16-game schedule is that you play everyone in your division twice for 14 games, plus 2 games against the team in the other division (but same conference) that ranked the same as you. So it looks like this:
The 2 division winners play in a Conference Championship, and winners of those games play in the Super Bowl.