Opus One, the label: S&D

Two of my favorite records are on this label, but I know there's plenty of uninteresting, or at least dated-sounding, stuff on the label as well. The records in question are Frederic Rzewski's "Attica" and Garrett List's "Your Own Self." The only other one I've heard is a Blackearth Percussion Group disc, which is okay but not something I get much out of on repeated listenings.

Milton Parker, where are you?
Do I need Max Schubel's "Son of Quashed Culch" LP? There's an affordable copy on eBay right now.