I get the jist of the worm drive modification, but personally a feel it's more of a fail safe than a permanent fix (well for piece of mind)
I now have, if anyone is interested? . . . a set of working standard CCT internals, spring, worm drive, plunger etc
I cannot verify the age or mileage covered on these but my bike ran noise free, and the bodies had 'Orange' dot's , as a rough guide of age ?
Anyway, drop me a pm if you want them

Dave