I use the standard ceramic stones with my KME, and so far I haven’t wanted for anything else. Maybe you already are doing this, but I’ve found that with sharpening single bevels on the KME – the required angle was slightly higher than I first assumed. If you have a 25deg. bevel, try setting your angle just a degree or two higher than that. I went from being really frustrated about getting my broadheads shaving sharp with the KME set at 25deg, to being able to do it in a few minutes with just that slight angle change. When you hit that ‘sweet spot’ with the right angle, it will be obvious.
Ron (aka Sharpster) posted a good little tutorial about it a while back on here.
Edit: just went back and read your post again, and it sounds like you’re just using a bench stone, and not the KME system. Regardless, I don’t think that diamond stones are essential for a metal with a Rockwell hardness of 52. And I’d highly recommend getting a KME, both for knives and single bevels!
