I tried going the thinner/shallower route for a while. In the end, I found it too much trouble. Some knives I'm really picky about, and for these I'll keep going with sharpening on a belt sander at about 12 degrees per side and touching up on the Sharpmaker at 15. For knives that get used frequently in a variety of places I've basically gone back to sharpening on the belt sander at about 17 degrees per side and touching up on the Sharpmaker's 20 degree slots. When this doesnt work, I go to the honing films at 22 degrees per side. When that stops, I go back to the sander. My goal is to keep a quickly sharpened edge as long as possible through microbevels, and only going back to the sander once every 6 months or so, when damage or bluntness are not removed by the other methods. On my Delica, the 20 degree Sharpmaker slots sharpen a micro bevel so narrow that its difficult to see without good light.
Basically, I recommend an angle 3 to 5 degrees lower than the 20 degree slots, chosen from the available ones on the system you have. This allows quick touch ups at 20 degrees, which will produce hair whittling edges with the standard white stones, and sometimes the brown ones. Shallower angles cut better, but take longer to sharpen because you have to remove more metal. As the microbevel angles go higher, the slight decrease in cutting is barely noticable. You could always try the same thing by sharpening at 10-12 degrees and touching up on the 15 degree slots. If you dont like it, its easy to go up to 20.