Half shelves are very useful to improve air movement in the kiln. Some kiln manufacturers recommend placing shelves directly on the floor of the kiln. This creates an insulating layer much like a storm door. Setters and Stilts Air movement in the kiln is clearly a big consideration - one of the most important when loading a kiln. Ceramics need to heat uniformly to prevent warping and stresses in the ware.
Air needs to move around shelves and around individual pieces.
Plates and tiles benefit from the use of tile and plate setters or stackers. Shelfstyle setters allow air to move under the large flat objects so they heat more evenly. Avoid heating large flat objects directly on the cooler shelf. If you are firing decorated tiles or plates, vertical setters economize on space, and sets can be stacked to fit even more. Glazed ware needs to be stilted or dry footed or the melting glaze will stick the ware to the kiln shelf, ruining both.