I ran a WMO mix in my '83 300SD for a couple thousand miles before selling the car -- the wife had a newer E300D and the 300SD became superfluous.

I was using a centrifuge, a 120 gph pressure-driven one from PA Biodiesel.

Lots of uncontrolled variables; I didn't know exactly what was in my oil, since I collected it from multiple sources on Craigslist.

But my experience can boil down to this: the more passes you do with the centrifuge, the better your results will be. I was able to centrifuge (25+ passes) even diesel engine oil to the point where I could see a little bit of light through it when pouring, though I never did get it to stop being black.

The car never gave me problems on WMO, other than lots of smoking (which may or may not have been the WMO's fault -- it was a long-neglected car), but my truck had major reliability issues on WMO/diesel mix. I ended up giving up on it for the truck.

I think there's a lot of promise, but I eventually decided the time I was having to invest wasn't worth the payoff.

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Lots of diesel W126s in the past
Current: 1991 Toyota 4Runner with an OM603