Disagree on the amount of videos: in my case, there is absolutely no correlation between the videos I am able to watch for greens or for bonus. When, one runs out, the other still works.
I have checked. If I have available videos to watch, there is active button for 2x bonus training. If I have watched all of them, the button is inactive.
It seems I was right and 2x bonus training uses videos from the same pool as rest pack videos.