Thanks PSU (I'm a PSU alumni, by the way, and so is my wife). I did my best considering it was my first DIY.

I hope nothing is in any way confusing, but it's hard to get some of these pictures because of the small nature of some of the parts. But just to reiterate a point from the edited Step 5, the OEM knob nut that you remove in step 1 has a lip on it, which is facing "up" when you unscrew the OEM knob (you'll see what I mean).
The way the JDM boot is configured, there's two small plastic tabs around the top rim of the plastic top circle piece (the piece that's nearest to the knob) which snap OVER the knob nut. If you put the lip up so it's right up against the new shift knob, those tabs won't snap over it and it keeps sliding around and down the gear shift column. The edit I put in simply reverses the nut direction so the lip is facing down (toward the bottom of the car) - this enables those plastic tabs to snap over it and stay UP!
I didn't notice this until I just took the car for a spin to see how it shifts. I fixed it and now it's really good. It feels good to shift.