Right.
Wag, BDL and Jon thanks heaps for your time and input.
Bugger, I had really hoped that guiderails on the back of the knife would have solved pretty much any angle problem by removing normal wrist wobbling. After all, you just would have to keep a decent downward pressure to make sure the blade is always in contact with the stone and the guiderail would do the rest, wouldn't you think? Evidently not - and if I understand your hints, this might be due to improper burr removal or, simply, the guiderail's help is not sufficient when going on the 6000 grit stone, where probably a minimum movement is sufficient to round up the edge or something.
Sharpie will be my new friend. I'm going to use it and see what it reveals... thanks for the lead.
Now, after a bit of thinking I've pretty much decided on the petty. And the decision is absolutely irrational: I'll be going for a Kanetsugu Pro-M 150. Rationale? I like the shape. And it's a different metal than VG-10 so I guess it broadens my horizons a bit although it doesn't sound as being one of the most celebrated alloys. Bah.
As a consequence of the petty's choice, I still wouldn't have experienced pure "Japanese-ness" in a knife and have just a hole in my knife block for a slicer... that needs fixing. (But that's something for another thread, 's my guess)