I have been re-watching your NAB video and I finally figured out how the weight works, now. I have my Xpresso setup and I see my beat in the User Data field of a null object I added to the scene.
My next question is, how do I get the user data recorded so I can use it in a time track? I noticed in your video, that all your user data fields have the red dot next to them indicating that there is a keyframe for every frame of User Data. When I turn on auto-key and press play, I see my user data changing, but no User Data keyframes are recorded. I guess that autokey frame does not record user data.
Ok, I figured out that you have to bake the null that has your user data and make sure the Parameter check box is checked in the Bake dialog.
So I have my baked data for the snare track.
I have a Random Effector moving left to right and I want my snare to control that motion. But I can not drag drop my Snare User Data track in to the time track field of the Random effector.
Whats the next step?
I tried copy and pasting all the data in my Snare track into the Time track, but the paste never works.
The paste occurs at the current frame, so you have to make sure your time line is at frame #0 before you paste.
It is actually working now....cool.