One of our favorite tactics on Facebook is to create top of the funnel video ads using lookalike website traffic or lookalike buyer information.  We usually cut that audience using Facebook Audience Insights of existing buyers to at least narrow age range.  Facebook video sometimes get a bad rap for counting a “View,” after the seconds, however the only metric I care about is the number of people who watch the whole thing.  We then create a custom audience of people who have watched 95% of the video and begin to re-target them with click then eventually conversion ads.  However, when you are trying to expand that audience very quickly you have two simple options; ramp budget on the top of the funnel video or create and start to target an audience of 75% viewers.  It gets complicated when deciding whether to then exclude the 95% viewers from the ads targeting those that are targeting the 75% viewers.  Turns out Facebook thought of this for you:

Creating an audience off of the people whom viewed your video is going to pull information from people who viewed that dedicated portion or amount of your video. Please keep in mind these numbers are not inclusive. This means that people who viewed 95% of your video can definitely be more than people who viewed 75% of your video, because these numbers do not include one another.

For example, you can have a total of 5000 people watching your video, with 3000 people watching 95% of it and only 2000 people watching 75% of it. This may seem weird because you would figure that the 75% would include the 3000 people from the 95%, but that is not the case. As soon as someone hits that 95%, they are included in the 95% of people, which is completely separate than the 75% of people.