Haven't heard Hal's CD, but I agree with Sam. Even if the track you are playing along with is tempered, it's a different and very valuable exercise for fine tuning technique. I often put on a metronome to a slow tempo, play an excerpt that I'm working on on the piano, record it, and play along with that. You don't have to have crazy piano chops to play something slowly that you would play on the bass.
In the old days, I would make a new version when I was ready to speed the excerpt up, but these days I just use the Amazing Slow Downer app to speed it up gradually. The loop function is also excellent for working on stuff that you want extra reps on because it will be exposed in actual performance. I find this a great way to choreograph the body motions needed to play the thing in tune at a slow tempo, and the body is pretty good about speeding those motions up by making them smaller as the tempo increases.
In the old days, I would make a new version when I was ready to speed the excerpt up, but these days I just use the Amazing Slow Downer app to speed it up gradually. The loop function is also excellent for working on stuff that you want extra reps on because it will be exposed in actual performance. I find this a great way to choreograph the body motions needed to play the thing in tune at a slow tempo, and the body is pretty good about speeding those motions up by making them smaller as the tempo increases.