I fired the kiln on Friday. It was very claim warm day (80°F outside) until toward the end of the firing (about 2000°F), then the rainstorm came with gusts from the south. The winds started sucking air out from the kiln, and the oxyprobe reading hit zero. I needed to lowered the gas pressure while closing the damper, and close the windows at the studio. It heated up the studio very quickly, close to 100°F. It lasted about 30 minutes, and became less windy so I could open the windows. I opened the kiln today, and it was another good firing. I guess the oxidation at the later stage of the firing did not affect the result.
Here is before and after pictures. Glazes do not have the same color before and after firing. Glaze is a glass structure over the clay, and its color is refection of the metal particle inside the glass, and varies by the thickness of the glaze application. The thickness is hard to measure and observe. Redish color is from the red iron oxide.
These are new saggars with fireclay. It shows different colors on outside, tan and white, that reflect reduction and oxidation. However, I got good reduction inside the saggar as well as the bowls stored inside.