Hi Tom,
In thinking about it, I don't think I've ever been in WBC on a DC-10 - I have been in dom 1st on United in a DC-10 but that was ages ago. Alan's descriptions will certainly be more entertaining than mine. The big thing to me (I'm 6'4") was that the NW A330 was so much more comfortable than the KL 777 in WBC. On flat vs cradle - hmmm - I recall spending more time in the gynecologist's inspired cradle than in the slide off flat. I'm fairly thin so I was able to make the cradle and the flat work for me. A more rotund passenger would probably have a harder time with the "flat" setting.
I don't tend to get too critical (generally) on WBC as I'm so incredibly thankful that I'm not in cattle class. Have a great trip.