I can't speak much for the cedes's, but I can say that little red is already having trouble pulling the gear oil through the fuel line. I'm assuming it's a fuel line restriction, possibly a smashed section, possibly a kink etc... Everything is on D2 right now because of unrelated issues. It'll be at least another week before I can get the processor moved and back up and running. Last winter I ran pure or almost pure WMO through ****** (my one ton ford), kept one tank D2, and the other my fuel. There were several days where I had trouble running it, not because it wouldn't burn it, but because it couldn't get it through the filter and lines fast enough to feed the draw. I have no heat exchangers or any type of added heat on the truck.
Little blue is already having starting issues, but that is due to preglow not functioning properly. Red will start and run on it now, but can't pull it fast enough to feed the draw. Were are seeing temps in the low sixties high fifties in the past week. My wife was running a 50/50 gear oil D2 mix til yesterday, it started perfectly, but even on that 50/50 mix she complained of having starving issues two days ago in the morning. Once the heat exchanger had some heat it went away.