Was reading the other questions, and just thought, would you consider making a video like a few seconds long that's like "I am making another history video" Could be an easy way to get the word out that you are making another history video to 100k+ people.
i've thought of doing stuff like that, and in the end i always decide not to do it. makes me feel like i'm not really in control of what i'm doing. might do the banner announcement though, like last time. but that only happened about a week before the end