just popped mine on.
didnt file the thread all the way down so it was flush as i wanted a snug tight fit, and if it was too tight I could always file a little more. mm's of difference.
Anyway, they look great, but by hand do seem very wobbly and i have set them pretty far back. about a fingers depth behind the top lip of the diffuser.
If they fall off no biggy, but will get two jubilee clips asap for the b*ggers