Eight means you probably have to lose conference championship games or go to an 11 game regular season. Sixteen means both go. In either case, the ninth and tenth or seventeenth and eighteenth teams will still pull the same card Baylor and TCU are pulling right now.
I like four. It means teams are going to have to consider scheduling Portland State. If the Big 12 doesn't like 4, tell them to bring Cincinnati, BYU or Boise State into the fold. Or just tell Baylor to schedule real teams in the non-conference in the future.