I convex my edges with diamond rods. It requires a bit of a "rolling" motion as you draw the edge across the rod, but it works pretty well if you can do it reasonably consistent. On flat stones, I'd do by pulling across with the back of the blade leading instead of pushing with the edge leading, kind of like you'd use a strop.
I even got a compliment on the edge I did on my first Ka-Bar Becker Necker from Ethan Becker when he and one of the engineers got ahold of it for some destructive testing. Yea, me.
sandpaper and a mousepad are your friends when convex sharpening. trust me, you tube it, only way to go, do all my axes this way also. stock up on 6 or 7 grits and go to tons. The weight of the blade compresses the mouse pad enough that it works perfect