My guess is the selection criteria specifying top 6 conference champs get an automatic bid would have a qualifier that auto bid teams be ranked in top 12 or 15.I don't see them adjusting the auto-bid related to conference size. They know they'll get a majority of the at large spots already. They'll just be motivated to reduce the number of auto-bids to allow more at-large for them to gobble up. In the initial proposal, there was to be auto-bids for the top 6 conferences (P5 + top G5 in essence). If the PAC dies, I'd imagine that'll reduce the auto-bids by one even though it was worded as the top 6 conferences and not tied to specific conferences. Will be interesting just how much power the non-P2 conferences have in this process to reign in the P2 domination of the CFP selection. In theory, they have more voting power. But they'll need to work together to keep thing equitable.
This year Tulane is the top ranked G5 school at #19 and Liberty is at #23. If there was a 12 team playoff, doubt P5 conferences would feel those teams are deserving even at this point. Liberty has Arkansas this week and Tulane plays UCF, Cincy and SMU. We could have a year where no G5 school is ranked in top 20 after CCG weekend.