I have two shelves worth of pottery-wheel thrown pieces ready to bisque! These oversized, wide bowls are in various stages of dryness and are the same type of clay body.
As clay dries it lightens, and unfired clay that's unglazed can be stacked to save space in the kiln. It's my habit not to stack more than two pieces high to avoid cracks along its base. Once bisque fired, the clay will brighten to a shocking peach.
I programmed the kiln to preheat for hours to ensure the pottery dries completely before firing. The preheat temperature of a kiln is around 187F (86C). Firing damp pieces at the boiling point, 212F (100C), will cause your clay to expand. Wet clay heated to 752F (400C) will explode from the force of escaping steam. Always air dry greenware until it is bone-dry, or preheat the kiln for a determined time.