You can make your life much easier if you make the source footage for your banners the same size as your stage, e.g. Banner 1 is 4752x144
I have simplified your workspace down to 1 banner and 1 surface, but it shoiuld be obvious how to expand it to your full 3 banner workspace.
Workspace and Screen recording attached. The motion is a lot smoother than the screen recording suggests but getting 20s screen recordings to fit into the 5MB limit of the Google Group is a challenge.
I still think the best way of doing this is to prerender the scroll and just loop the video cue.
Mic