Herbie's Hal-O tube dampener's on Calypso?

I have used Herbies Halos for quite some time. On EL-34s, 6SN7s, and multiple types of mini pins. In every instance there was an improvement in sound, but that is not to say some experimentation was not involved. Steve counseled me that the use of the Halos are not an exact science. You will get different results depending on how they are used. On my preamp, I started with the gain stage, then the buffer stage (Cary SLP-98). First on the middle of the tube, then moving it up gradually. I finally settled on just below the top mica. As for the amp, same method, but they seemed to work best above the top mica on the EL-34s. Now on my Joule Electra preamp and Hagerman Trumpet phono stage, they are used in the middle of the tube, as closer to the top seemed to take some of the naturalness out of the sound. I learned a lot depends on how well the designer has dampened the area where the tube sockets are mounted, as well as how microphonic the tube is to begin with.