I haven't made much more progress in the last 6 weeks. I've been really tired and sleepy at night, and I've completely lost the ability to keep myself from drifting straight off to sleep as soon as I get comfortable and relaxed. Since I haven't been keeping up with the practice exercises, I didn't think it was smart to keep reading ahead in the book. Maybe there's no sense to that, but it's my opinion.
Also, never try this stuff with a nasty head-cold. Coughing, sneezing, and hacking up phlegm-balls aren't particularly conducive to achieving a relaxed state.
I did have a brief episode of the old vibrations sometime in the beginning of October. The book mentions this fairly frequently, so when it happened I got pretty keyed up and excited. Of course, getting keyed up and excited are pretty much the exact opposite of relaxing and blanking out your thoughts. It might be progress, I'll just try to handle it better.