Well there was no good news for me today. (Perhaps I should not have scheduled to open the kiln on such a black day in history.) Everything is a mess. With few exceptions--those being test tiles and small test bowls--everything has serious pinholing problems. I have finally found a clay that is vitrified at cone 6--Cinco Blanco by Armadillo. But everything is pinholed. My friend Herb pointed out similar pinholes on bowls he had made with Cinco Blanco. The glazes are ones that I have used successfully on other clays--which, unfortunately, are not vitrified at cone 6. Maybe I am chasing the wrong rabbit--not everyone seems so concerned about using vitrified clay.
I spoke with Armadillo Clay about my experience. It was recommended that I refire and take the firing temperature up a bit higher as the common wisdom says pinholes are the result of underfiring. The conflict is that Armadillo Clay stresses that one must not fire Cinco Blanco above cone 5. I am getting a cone 6 touching in my current firing schedule. So I will reload the kiln and refire.