Thankfully, (maybe) my memory is not as good as yours is. I have these smatterings or memory that tell me I recall something or other about the subject. Nothing conclusive enough to go in search of the tidbits.
Actually I was a pretty serious fan of Levin's in the first half of 2000s and I bought his book on the Courts in 2004 and he wrote a chapter about this very subject,
In his book he said that filibustering judges (with <51 ) is unconstitutional. But once Obama won he insisted the GOP filibuster every one of them.
I understand its the talk radio business and why he would do this, but his interpretations are repeated here by more than a few as if he is Moses coming down from the Mount with the US constitution on stone tablets.