Barry, glad you liked the 204, I hate giving bad advice
If you can get the higher grit stones, you should be able to get a polished finish. I'd be really curious to know what kind of results you get; and you're right-it would be a great alternative to those who don't want to spend the cash on the Apex. They should buy one anyway though!
Bothrops, I'm glad you liked my review, more importantly I hope it provided you with good information. Now, as for your quesions:
The Apex allows you to set the angle of the stones (and therefore the edge) at ANYTHING from 10-25 degrees. It's not problem to cut a relief angle and then a primary cutting edge. I haven't tried this on my knives, but I'm very familiar with the principal. I'm a woodworker and all of my chisels and plane blades are gound with a secondary or mirco-bevel.
The advantage of water stones is that they cut VERY quickly, much faster than oil stones. The disadvantage is that they wear more quickly too. I've used water, oil, and diamond stones and I prefer water. Just my opinion though. If you can get substitute stones in 1/8" thickness and some blanks for Ben at EdgePro you can use those instead of the water stones. As long as you keep the thickness of the substitute stones the same as what the apex was set for, it won't affect the pre-marked angles.
If you're going to remove the black coating to form a relief, it is possible to get corrosion. It's not much of an issue on the primary edge because use and sharpening will remove all rust. I'm not sure about the relief edge. However, Sentry Solutions' Tuff-Cloth is a great corrosion inhibator; I use it on all my knives. One thing, before you cut a relief in all your knives, try sharpening one of your knives with as perusual on the Apex and see what you think of the edge, you may find that your don't need the relief to get the edge you want. Keep in mind that all my knives are sharpened at 21 degrees and they don't so much cut as they disolve.
I hope this helps you and if you have any other questions fire away!
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"Better to reign in Hell, than serve in Heav'n"
John Milton
There are only two types of people; those who understand this, and those who think they do.