The gray squirrels will prevail, but I refuse to give up the fight. They have even started drinking from my hummingbird feeders. I wonder if any of them will be become diabetic from all that sugar.
My latest deterrent method is a combination of a suspension wire, a baffle and a pivoting support.
The suspension wire is no problem for the creatures, they are natural high wire acrobats. The baffle is a re-purposed brass cymbal which tips on it's support. Beneath is a balance beam with matched feeders.
The squirrels can easily negotiate the high wire and the tipping cymbal but the the balanced feeders tip with just enough velocity to drop them off. If they would coordinate their attack then two squirrels could defeat this arrangement by climbing onto the feeders in unison, but I haven't seen that yet.
I had a twirl-a-squirrel but while it was fun to watch, it tended to self activate on windy days. After I dropped it on a cement floor it shattered into a million cheap plastic parts. Still if you want to try: