Timing an event to have maximum effect on a presidential election

Politics & Elections
#1

Suppose that you were someone with a lot of power to sway a presidential election outcome - maybe you’re a movie producer releasing a movie that will change the views of millions of voters, or you’re a foreign government with the power to influence a U.S. presidential election outcome (for instance, China suddenly doing something militarily/politically drastic), or a whistleblower with knowledge of a political scandal (i.e., bribery, murder, etc.) that could bring down a candidate.
What would be the best timing for you to do so?
3 weeks before the election?

1 week before the election?

3 days before the election?

#2

Obviously you have weeks of sensationalist advertising leading up to a fantastic event followed by additional events leading into the election.

#3

When was Citizens United planning on releasing that video slandering Clinton?

#4

Perhaps you’ve heard the term “October Surprise” to describe exactly what you’re talking about. According to the cite, the prime dates have been:

1968 – October 30
1972 – October 26
1980 – at least a month before the election
1992 – October 30
2000 – November 3
2004 – October 27, 29
2008 – October 31
2012 – September 17

Except for a couple of outliers, it would seem the prefered time for a sensation is the last week before the election.