12, this will be more open to both sides.
The goal is to play the game 5-6 times every 10 years.
So, do a home and home twice. That is 4 games.
Then, have a deal with a bowl game. I used to say the Vegas Bowl, but that isn't possible anymore. But if Utah and BYU don't qualify for the playoffs or the Rose Bowl or the Vegas Bowl or a NY Bowl, then they meet against each other in their bowl game. I don't care where, as long as it's not El Paso. That would suck. But somewhere in So. Cal would be a ton of fun.
That would probably happen 1-3 times every decade.
The rivalry game as a bowl game in sunny So Cal in December? That would be awesome.