just ran .75 L of lubromoly diesel purge from a 1L bottle and ran the return back to the bottle... knocking seemed to go away after a few revs... took it on the road and swapped back to the regular fuel system when i was down to a quarter L in the bottle. dumped the left overs in the nearly full tank that i'd already put about the same amount of slick 50 diesel kleen in.

Will see in the am how it affects the knocking.... my drip tube just arrived as well so i'll check timing next.