Many thanks for an interesting log. I've not done the watt passages, except Delfzyl-Norderney, but most of what you report agrees with our experience (5 times). It's the little things, like where to get diesel that can be so helpful.
In spite of your scare with the "Gotland", the Kiel canal can be quite a relaxing experience and the passage can be comfortably broken at Rendsberg if desired. I agree the Elbe is not a good place in a gale, though the Cuxhaven-Brunsbuttel section should be manageable in a boat of 30' or so.

PS I've just tried the site again and it seems to be down.