Since you freehand sharpen, you might want to invest in one of the diamond rod sharpeners that Emerson sells. They're oval shaped so they fit well in the curved section of the recurved blades Emerson makes. The 15s are not as severely recurved as the Commander series, but it's still enough so that I didn't like using a flat stone when I sharpened mine. I did well with their diamond rod sharpener, however.
As far as toothy vs. polished, I always preferred my Emersons with a toothier edge. They just seemed to perform better on the material I was cutting back when I was carrying Emersons. I would sharpen with their diamond rod and then run both sides of the blade down the edge of a bare, hard leather strop a couple of times. That seemed to do it for me on my mini-15.