I actually just got one of the blue PWJDM knobs about a month ago. Installed it without any issues. Mine sits/fits perfectly so you actually shouldn't need to use any loctite at all.
It was late at night and my memory's a little fuzzy but.. if I remember correctly, the little black ring was held in place by a wire tie. I had to cut the tie to lower the ring to get the stock shifter off properly. Then after the stock shifter was off, I raised the ring a little bit higher than it was before and I tied it back the same way. Luckily the boot had some extra slack at the top and when I lifted the ring a little higher, it also become a little more narrow, so it was a good fit with the smaller PWJDM base. The thing that came with the shifter goes inside the knob (nothing goes underneath the black ring).
The little washer that was inside your stock shifter though.. you should leave that out. I thought it helped the shifter sit on the threads so I kept it in there, but it will rattle around and make noise. I took it back out and it's been perfect since.
