If the Masters ending is "normal" on Sunday, my experience has been that with the Butler Cabin baloney it takes until about 710pm unless there is a tie. Augusta is reasonably far west in the Eastern Time Zone and official sunset will be at 756pm Sunday.
Today, Saturday, the third round ended at 702pm and commentary followed.
Here are the rules for a sudden-death playoff: In the event of a tie, the players who are tied will tee off on the 18th hole in a sudden death format. If a player does not emerge as the winner on the 18th hole, the players will go back to the 10th hole for the next sudden-death hole. Players will then move between the 18th and 10th hole until one player is left as the champion.
Let's assume that there is an extended sudden-death playoff (this seldom happens) until 8pm, then 20 minutes of CBS baloney. That puts the start of 60 Minutes at 820pm if by bad fortune that did happen.