I ended up trying the BBW slurry before reading your reply, figured I couldn't really hurt the coti that much.
It built up a nice layer of blue slurry, nary a drop of yellow to be seen. It usually takes me a lot of effort to get a good yellow slurry with the slurry stone - lots and lots of elbow grease actually. But this BBW side laid down heaps of slurry right away. I was able to make it look like my Escher after using a DMT plate.
So what did I do with it, you ask.
Prior to that I had dulled a Fili #14 EPBD, set the bevel with thick yellow, then diluted just a couple times. At that point it was a ++ for shaving arm hair. I've never done a HHT, since this was my first attempt to start from a dull blade and I was just trusting the power of the hone.
I made the BBW slurry rather thick, did around 30+ strokes, then started diluting slowly. A small spray every 30-50 strokes. I don't count, I get lost in my moment of zen. Diluted all the way down to pretty much no blue. Looked at the bevel with a 16 loupe and it was mirror finished. But I didn't see much improvement in the ability to shave arm hair.
Washed the hone and blade, then put soapy water on the coti and started another diluting process, all the way down to fresh water. Then washed again and used plain water for many strokes.
The shave today was rather nice. No rash or burn, no cuts or nicks. I do 2 passes everywhere except the chin, where I do 3 passes. The chin is actually BBS, which is damn rare for me. The rest is good enough. Beginner's luck :thumbup:
Before this I have only played around with the slurry on a random no-name razor, just getting practice doing strokes and building/diluting slurry.
Next time I will just stick with the yellow slurry and dilute all the way down. I got a Kabeso off the bay the other day, will try again with it.
cheers,
jeff