What if (very likely) the B1G comes in and takes a few (not going to mention any specific teams, don't get hung up on that, just the overall idea)

You definitely then have a P2.

But which of these future decisions maximizes their value?

Does B1G go to 16 also and they both stop - then you still have remnants of the ACC/PAC/B12 in the national conversation? (even though they really won't be) This keeps SEC/B1G schedule options open, fits the proposed 12 team playoff, lets ND stay independent, keeps large portions of CFB fans with their teams technically in the highest level, etc.

Or, does the SEC and B1G add until both have ~20 and truly split the highest level college football world into two halves? (and the have nots) They'd have more mouths to feed, but it would be a definitive dividing line - teams outside of this might as well truly drop a division - or create a new one. Would the consolidation make the CFP that much more profitable to afford the extra mouths? or would they lose fans to the now lower level? - to the extent it is better to stay at 16 and keep the "G3" around?

IMHO VT would be on the bubble there, and I'm going to watch them no matter which conference/division they play in. So if VT didn't make it, the two mega conferences would lose me as a CFB fan - I might watch the championship the same way I watch the Super Bowl, but not the NFL - but I wouldn't be a rabid fan, watch other games that may affect VT, etc. and based on comments I'm seeing about the direction of CFB in general, I think a lot of people would feel that way.

Some serious financial ciphering required to determine which would be more beneficial....