[Adam Skelding]

The white dust is just slipper pad material from your slipper slipping. Unless your D4 has been doing some laps in Hollywood.

If you build the slipper as per the instructions it will 'automatically' slip independently. The is no way of adjusting the slip front to rear, it just allows the slipper to function independently. However, if you notice there is another hole in the layshaft. If you put another pin in here and build the slipper, the slipper will act more like the 'old' version, but you will have the advantage of external tune-ability.

As for threadlock. I dropped a blob of blue loctite 241 on the nut. Just basic bullet-proofing it can't come undone then, but still allows you to adjust.