Only 8 hours sounds much better. I work slowly as well and do tend to swill a bunch of icy cold beer when wrenching on the diesel. Sounds like a full weekend to me!
Didn't realize that snaking the oil cooler lines in there was so tough! I have a 300SD so perhaps there is a bit more room under there than your 300D.
At the same time I do this job, I am also replacing the turbo oil return line seals and the oil pan and gasket (oil pan was dented somehow by the previous owner and the gasket is seeping). The turbo oil return seals aren't leaking (yet) but if I have the pan off to replace its gasket, I might as well replace the other seals, as they will leak eventually.
I also have some oil seepage from under the air filter housing where the separator drains back to the pan. I think that rubber gasket under there is shot.
Now that I think about it, I also have some leakage from the front crank seal, but won't attend to that anytime soon.
My oil leakage has decreased dramatically since I switched back to Delvac 1300 from Delvac 1.