I wouldn't worry about the middle...or at least, I wouldn't bet Denver just for that reason. You Indy bet's a winner (unless the Colts become the Houston Oilers).
I'm already on Indy -3 and Under 49. That's probably a split, but I'm taking Under 23 to hopefully offset the full-game Under. Still possible both could hit.
Denver will go on fourth downs..and probably not complete too many of them...indy will run the ball no need to score when up by so many points...i expect at most 14 pts to be scored