After three weeks of practice, I listened again to Diane Bish's performance and discovered something interesting: she plays it slower than she has indicated on the score. She indicated quarter note = 100 on the score, but, when I checked her performance with a metronome, I found that she was playing it at quarter note = 80. For some of the piece she played a little quicker, but always came back to 80. 80 is something I can deal with. I like 80. 100 does not seem humanly possible. I am going to assume that the marking on the score is a misprint.