I WAS LOOKING AT THIS THREAD IN HOPES FOR A SOLUTION BUT CAME UP WITH A METHOD TO MAKE THIS HAPPEN:
1. Enter Visualizer (command+T)
2. Enter Mission Control (I swipe Up on my trackpad with 4 fingers)
3. Click and Drag the Visualizer screen to the Monitor you want to display it on. (I use 3 finger drag method)
Simple solution to a frustrating desire. Now I can compute with the visualizer and music YES!
OH MY GOODNESS, THIS ACTUALLY WORKED!!! Thank you so very much for this