Some folks say that cotis will only get you to around the equivalent of 8K synthetic. Folks report they can get a really good shave after a progression with a Norton 4K/8K combo stone.

I tend to agree with finishing on the coti with weight of the razor and running water or glycerin and water. I have even tried doing 10 laps really light on the dry coti. I generally finish with a Vermio or CrOx on balsa after a coti progression.

If the shave feels good and is clean and smooth, HHT doesn’t really matter. The ultimate criterion for a test of an edge is shaving the facial hair, not snapping individual hairs.