What has been said is all true.
The OP states he is using a "bout"
While it can be done, it isnt as easy on a small piece of Coticule.
It is just another variable that adds to the equation.
Keeping with methodical. Consider using your synthetics to 8K, then use your coti to test your edge.
Improvement/refinement= good. Then test your 12K and use same method water and coti and test.
Setting a bevel and dilution to a finish on a coti is romantic, and possible/plausible.
The variables are experienced honer and a special Coticule.