Okay, working! I've got a prop with a y-axis dependency to the V4 morph BrowUp-Down. When you grab the ball and move it up/down, the brows raise/lower.

Click here for short demo vid

Thanks shvrdavid and ghostman.

I may or may not abandon my "18 helper bones for facial animation" project. First I want to see if this idea...prop with morph dependency...gives me the control I want.