David,
I'm not sure I see the value in the japanese waterstones. After using the stone grader on the tormek stone you have a 1000 grit stone, so the 800 grit doesn't offer you anything. As for the 4000 grit stone, I get excellent results after stopping at the 1000 grit stone and honing.
Another lost advantage, assuming you start sharpening with the tormek stone and then replace it with the japanese stone, is losing the geometry of the setup. I think an advantage to the tormek stone is you set your jig up for the current diameter of the stone and then using the stone grader you can sharpen at two grits without needing to re-adjust your setup. If you replace the tormek stone with another stone of different diameter, you would have to re-adjust your jig with may turn out to be easy or a pain.
If you did want a finer finish than the tormek stone can give you, I would suggest buying some of the superfine wet/dry sandpapers to finish with instead of spending $160.
Just my thoughts,
Tim