12 is perfect. Or at least pretty close to ideal. A true playoff would need to be 16 teams, with every single D-1A league getting a bid, which is how you'd have to do it. It's not really a playoff if half the teams in the same classification are simply getting shut out. Because that's not how it works. But this is big-time CFB we're talking about, and most of y'all are just here for the gangbang, as the saying goes. So none of you give a F about anything like that. Like making sure that every team within a given classification has their due process so to speak. That's for woke little bitches.....
And with that in mind, 12 is a good very good number. You get all the P5 conference champs, who earn their way in, unaided, no faceless bureaucrat deciding their fate. You throw a bone to the G5 and they get one, they're guaranteed at least one. So they're covered, sort of. And then you have six at-large bids, decided on by the committee. And all six of those teams will be totally good teams.
And then you can have the first round with four home games and four byes, the 2nd round with four more home games, then the semifinals, which I really hope are also home games. And the final - the national championship! - at a neutral site, between the two teams who survived the gauntlet and made it to the end. The whole thing consists of four rounds over four Saturdays, and takes three weeks to complete. Nothing but pure awesomeness.....