It has been suggested on another forum that the heat from the elements evens out approximately the same distance below the elements as they are apart. So if you elements are 50mm apart, then the heat will even out about 50mm below the level of the elements.
I point this out so you know that anything closer to the elements than they are spaced, requires very careful firing – slow, very slow – to avoid breaking the item. It can be done. I have done it. others have done it. But the firing needs to be very slow, and you need to watch to see when it is fully draped, but not stretched. The watching is done in quick peeks, without opening the lid/door if at all possible.