Before I pester Ardennes with my questions (given I'm not sure if I'll be buying soon or not). Thought I'd see if anyone here knows the answers first.

I've noticed on the site that they don't recommend the standard bout for razors. The best of my four cotis for razor finishing (with my limited experience) is a standard bout bought from a third party seller because it was cheap and I thought I'd gamble. My select grade direct from Ardennes is all round amazing, fast and fine enough to finish, little soft so need to watch for slurrying. A standard grade from another third party is soft and too coarse. The latter two mentioned are both rectangular stones. My question is regarding the bouts, are they grading them just the same as rectangular stones? Purely down to surface homogeneity? Or also the shape of the bouts(easier shapes/more rectangular) for honing?