Just as I finished writing that last post on SAX 2261, I discovered this:
There is an uploaded sound clip of the record! I just spot checked it, and it turns out that it sounds pretty much the same as my pressing. Loss of clarity during the loud passages. So perhaps this is just an issue with the record!!
Upon re-listening to the Maazel recording of Pictures (SAX 2484), there is also some loss of clarity during some of the loud passages. It still sounds a lot better than SAX 2261, though. If someone out there has a good explanation for the distortion in the dynamic passages, please share your wisdom with me!