Diamonds seem to be a good choice for the "typical" highly wear resistant knife steels in pocket knives nowadays. They work - consistently - regardless of whether you are sharpening 1095 or S90V.
If I recall correctly, the Buck Avid is 13C26. You could use coarser waterstones like a Shapton 1000 or other popular 1000 grit waterstones as well.
I don't hear much about belgian coticule being used for pocket knives--mostly kitchen knives and straight razors. Since pocket knives typically don't have the edge geometry of a good Japanese kitchen knife, they frequently may need to be re-beveled if you are used to much more acute angles.