First off, big upvote to snaroff for his searching ability!
On topic, I love to backhand the Spine Chiller in wh20. It’s always satisfying and often strategic — when you have 2 balls locked, third lock lit, flashing whirlpool and the Boulder award is 5x playfield so you can get that stacking, then getting to the upper pf is much easier and safer via backhand rather than a tricky timed shot from the right flipper.
Beyond stacking 5x pf and multiball, backhanding to the upper pf usually means a slower ball coming around to the upper flipper. So it’s easier to hit the shot you want, like for a combo.