the deed is done! I added dental bands to each of the sliders and I'm seriously enjoying the results so far. I didn't think of it at first, but this mod has eliminated two problems I had with stock HHKB. The upstroke clatter is now substantially dampened and basically goes unheard. Great success here.
Secondly, one of the problems I sometimes had after keypresses was that my fingers would bump adjacent keys as I was moving my fingers and preparing to downpress another one close by. This probably occurred because of the height differential between the fully depressed key, and the height of an unpressed key that's right next to it. As MJ45 said, the dental band actually affects the travel by lowering the start point of the key, which I realized after seeing how the sliders worked.
So far, so good. I'll need to break in this mod for a few days and get a solid feel. This still feels like HHKB and the great feel is still there.